Hi Peter, You shouldn't feed Vin via the P2.5 pin as it's output current source is 3.4mA with 12mA for all ports combined. Vin should be connected to Vcc of micro if this micro regulator permits and drive the enable pin from P2.5 only. You never mentioned you voltage source. I'll assume it's from 1 x lion cell as that's what your regulator is designed for being step up. The 55uA from regulator only is way off also. Do you have another part to try? Doe's it have to be this part, what are you powering? Good luck Dennis ----- Original Message ----- From: "Peter Grey" <martech@mart...> To: <msp430@msp4...> Sent: Tuesday, November 04, 2003 12:11 PM Subject: Re: [msp430] Problems with switching. > At 11:27 AM 04-11-03 +1300, you wrote: > > Hi Dennis > I have set P2.5 to and output and have not touched P2Sel.5 as it should be > set up as I/O on start up. The port is switching from low to high. The 55uA > is from the regulator only which is a little disconcerting as I would not > expect any current. I have the enable of the regulator wired to the input > line. That is, I switch both enable and Vin from P2.5. > If I set up the regulator with enable and Vin common and use a power supply > to switch on these lines all is OK. I will try just switching the enable > line and see what happens. I am wondering if I have a faulty batch of > regulators but it is all too easy to blame the component. > > Thanks for the help > > > Peter > >Hi Peter, > >I'll assume you have set P2.5 as output and P2Sel.5 as I/O. > >Is the port switching from low/hi? > >The specs say what you are doing is fine and you have tested regulator > >outside of micro so I have no idea. > >You say the regulator uses 55uA when enable is low. Doe's this include the > >micro or just regulator? > >If just regulator something is wrong. Are these figures true when you > >measure regulator only with enable low then hi? > > > >good luck, hopefully somebody else can be more helpful > > > >Dennis > >----- Original Message ----- > >From: "Peter Grey" <martech@mart...> > >To: <msp430@msp4...> > >Sent: Tuesday, November 04, 2003 10:53 AM > >Subject: Re: [msp430] Problems with switching. > > > > > > > At 09:17 AM 04-11-03 +1300, you wrote: > > > > > > Hi Dennis, > > > > > > As in a previous post I should have said FET EMULATION TOOL. > > > To avoid problems with my target board I set up the FET to do the > >switching > > > using a 1121A. When I had the regulator operating alone it was fine. When > >I > > > try and switch power to it using the FET, I get these high currents. > > > > > > > > > all the best > > > > > > > > > Peter > > > >Hi Peter, > > > >You obviously have something terribly wrong as the regulator is only > > > >designed to supply 25mA max. > > > >Drop the fet. don't need it as you can switch the enable pin from a port > > > >directly. In shutdown mode this is only 0.1uA, with pin enabled should be > > > >250uA. If your application requires low power consumption why not try the > > > >TPS76933, this has higher shutdown current consumption 1uA but lower only > > > >17uA quiescent current at full load, though this all depends what your > >input > > > >voltage is as part is a fixed regulator only. Is your hardware clean? > >flux > > > >residue etc. > > > > > > > >Dennis > > > >----- Original Message ----- > > > >From: "Peter Grey" <martech@mart...> > > > >To: <msp430@msp4...> > > > >Sent: Monday, November 03, 2003 4:50 PM > > > >Subject: Re: [msp430] Problems with switching. > > > > > > > > > > > > > I use a MSP430F1121A and it is usually in low current applications. I > > > > > normally switch power to external chips only when I need them to > >conserve > > > > > power. However, I now have a problem with this. I have a regulator > > > > > (TPS60240) which I provide power to via P2.5. I found the regulator > >was > > > > > drawing too much current in my circuit ( some 25mA with no load on > >it.). I > > > > > set up the regulator by itself and it draws about 200uA with no load > >and > > > >at > > > > > 3.0 volts which is about right. I then use the FET and switch power to > >the > > > > > regulator. When it is not switched high, the current is about 55uA and > > > >when > > > > > I switch it high it is 16.6mA! Again this is with no load. The > >TPS60240 > > > >has > > > > > 2 charge caps (1uF each) and an input and output cap (each 1uF). > > > > > Can anyone provide some clues as to what is happening? > > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > Peter > > > > > > > > > > > > > > > > > > > > > > > > > . > > > > > > > > > > > > > > > > > > > > ">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >. > > > > > > > > > > > > > > > >">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > . > > > > > > > > > > > > ">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > >. > > > > > > > >">http://docs.yahoo.com/info/terms/ > > > > > . > > > > ">http://docs.yahoo.com/info/terms/ > > >
Hardware architectural decisions
Started by ●October 28, 2003
Reply by ●November 3, 20032003-11-03
Reply by ●November 3, 20032003-11-03
At 01:03 PM 4/11/2003 +1300, you wrote:
Hi Dennis,
The regulator is used to provide 3.3 volts for a ADXL202 which draws 0.6mA.
I want a stable voltage even if the Li voltage drops below 3 volts. As the
regulator draws 200uA and the sensor 0.6mA the pin P2.5 should be able to
handle this??
However, I will set it up as you suggest and see what happens. I selected
this part because of the low current draw and have laid out a board to
suit. If I still have problems after all this I will select another part
and start again.
Thanks again
Peter
>Hi Peter,
>You shouldn't feed Vin via the P2.5 pin as it's output current
source is
>3.4mA with 12mA for all ports combined.
>Vin should be connected to Vcc of micro if this micro regulator permits and
>drive the enable pin from P2.5 only. You never mentioned you voltage source.
>I'll assume it's from 1 x lion cell as that's what your
regulator is
>designed for being step up.
>The 55uA from regulator only is way off also. Do you have another part to
>try?
>Doe's it have to be this part, what are you powering?
>Good luck
>
>Dennis
>----- Original Message -----
>From: "Peter Grey" <martech@mart...>
>To: <msp430@msp4...>
>Sent: Tuesday, November 04, 2003 12:11 PM
>Subject: Re: [msp430] Problems with switching.
>
>
> > At 11:27 AM 04-11-03 +1300, you wrote:
> >
> > Hi Dennis
> > I have set P2.5 to and output and have not touched P2Sel.5 as it
should be
> > set up as I/O on start up. The port is switching from low to high. The
>55uA
> > is from the regulator only which is a little disconcerting as I would
not
> > expect any current. I have the enable of the regulator wired to the
input
> > line. That is, I switch both enable and Vin from P2.5.
> > If I set up the regulator with enable and Vin common and use a power
>supply
> > to switch on these lines all is OK. I will try just switching the
enable
> > line and see what happens. I am wondering if I have a faulty batch of
> > regulators but it is all too easy to blame the component.
> >
> > Thanks for the help
> >
> >
> > Peter
> > >Hi Peter,
> > >I'll assume you have set P2.5 as output and P2Sel.5 as I/O.
> > >Is the port switching from low/hi?
> > >The specs say what you are doing is fine and you have tested
regulator
> > >outside of micro so I have no idea.
> > >You say the regulator uses 55uA when enable is low. Doe's
this include
>the
> > >micro or just regulator?
> > >If just regulator something is wrong. Are these figures true when
you
> > >measure regulator only with enable low then hi?
> > >
> > >good luck, hopefully somebody else can be more helpful
> > >
> > >Dennis
> > >----- Original Message -----
> > >From: "Peter Grey" <martech@mart...>
> > >To: <msp430@msp4...>
> > >Sent: Tuesday, November 04, 2003 10:53 AM
> > >Subject: Re: [msp430] Problems with switching.
> > >
> > >
> > > > At 09:17 AM 04-11-03 +1300, you wrote:
> > > >
> > > > Hi Dennis,
> > > >
> > > > As in a previous post I should have said FET EMULATION TOOL.
> > > > To avoid problems with my target board I set up the FET to
do the
> > >switching
> > > > using a 1121A. When I had the regulator operating alone it
was fine.
>When
> > >I
> > > > try and switch power to it using the FET, I get these high
currents.
> > > >
> > > >
> > > > all the best
> > > >
> > > >
> > > > Peter
> > > > >Hi Peter,
> > > > >You obviously have something terribly wrong as the
regulator is only
> > > > >designed to supply 25mA max.
> > > > >Drop the fet. don't need it as you can switch the
enable pin from a
>port
> > > > >directly. In shutdown mode this is only 0.1uA, with pin
enabled
>should be
> > > > >250uA. If your application requires low power
consumption why not try
>the
> > > > >TPS76933, this has higher shutdown current consumption
1uA but lower
>only
> > > > >17uA quiescent current at full load, though this all
depends what
>your
> > >input
> > > > >voltage is as part is a fixed regulator only. Is your
hardware clean?
> > >flux
> > > > >residue etc.
> > > > >
> > > > >Dennis
> > > > >----- Original Message -----
> > > > >From: "Peter Grey" <martech@mart...>
> > > > >To: <msp430@msp4...>
> > > > >Sent: Monday, November 03, 2003 4:50 PM
> > > > >Subject: Re: [msp430] Problems with switching.
> > > > >
> > > > >
> > > > > > I use a MSP430F1121A and it is usually in low
current
>applications. I
> > > > > > normally switch power to external chips only when
I need them to
> > >conserve
> > > > > > power. However, I now have a problem with this. I
have a regulator
> > > > > > (TPS60240) which I provide power to via P2.5. I
found the
>regulator
> > >was
> > > > > > drawing too much current in my circuit ( some 25mA
with no load on
> > >it.). I
> > > > > > set up the regulator by itself and it draws about
200uA with no
>load
> > >and
> > > > >at
> > > > > > 3.0 volts which is about right. I then use the FET
and switch
>power to
> > >the
> > > > > > regulator. When it is not switched high, the
current is about 55uA
>and
> > > > >when
> > > > > > I switch it high it is 16.6mA! Again this is with
no load. The
> > >TPS60240
> > > > >has
> > > > > > 2 charge caps (1uF each) and an input and output
cap (each 1uF).
> > > > > > Can anyone provide some clues as to what is
happening?
> > > > > >
> > > > > >
> > > > > > Thanks
> > > > > >
> > > > > >
> > > > > > Peter
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > .
> > > > > >
> > > > > >
> > > > > >
> > > > > > ">http://docs.yahoo.com/info/terms/
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >.
> > > > >
> > > > >
> > > > >
> > > > >">http://docs.yahoo.com/info/terms/
> > > >
> > > >
> > > >
> > > >
> > > > .
> > > >
> > > >
> > > >
> > > > ">http://docs.yahoo.com/info/terms/
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >.
> > >
> > >
> > >
> > >">http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
> > .
> >
> >
> >
> > ">http://docs.yahoo.com/info/terms/
> >
> >
> >
>
>
>
>
>.
>
>
>
>">http://docs.yahoo.com/info/terms/
Reply by ●November 3, 20032003-11-03
Hi Peter, I was just looking thru the data sheets and noticed the part REG710-33. 0.01uA shutdown mode, 65uA quiescent current when active, 1.8 - 5.5 v input, 6 pin device. Well worth a look good luck Dennis ----- Original Message ----- From: "Peter Grey" <martech@mart...> To: <msp430@msp4...> Sent: Tuesday, November 04, 2003 1:27 PM Subject: Re: [msp430] Problems with switching. > At 01:03 PM 4/11/2003 +1300, you wrote: > > Hi Dennis, > > The regulator is used to provide 3.3 volts for a ADXL202 which draws 0.6mA. > I want a stable voltage even if the Li voltage drops below 3 volts. As the > regulator draws 200uA and the sensor 0.6mA the pin P2.5 should be able to > handle this?? > However, I will set it up as you suggest and see what happens. I selected > this part because of the low current draw and have laid out a board to > suit. If I still have problems after all this I will select another part > and start again. > > > Thanks again > > > Peter > >Hi Peter, > >You shouldn't feed Vin via the P2.5 pin as it's output current source is > >3.4mA with 12mA for all ports combined. > >Vin should be connected to Vcc of micro if this micro regulator permits and > >drive the enable pin from P2.5 only. You never mentioned you voltage source. > >I'll assume it's from 1 x lion cell as that's what your regulator is > >designed for being step up. > >The 55uA from regulator only is way off also. Do you have another part to > >try? > >Doe's it have to be this part, what are you powering? > >Good luck > > > >Dennis > >----- Original Message ----- > >From: "Peter Grey" <martech@mart...> > >To: <msp430@msp4...> > >Sent: Tuesday, November 04, 2003 12:11 PM > >Subject: Re: [msp430] Problems with switching. > > > > > > > At 11:27 AM 04-11-03 +1300, you wrote: > > > > > > Hi Dennis > > > I have set P2.5 to and output and have not touched P2Sel.5 as it should be > > > set up as I/O on start up. The port is switching from low to high. The > >55uA > > > is from the regulator only which is a little disconcerting as I would not > > > expect any current. I have the enable of the regulator wired to the input > > > line. That is, I switch both enable and Vin from P2.5. > > > If I set up the regulator with enable and Vin common and use a power > >supply > > > to switch on these lines all is OK. I will try just switching the enable > > > line and see what happens. I am wondering if I have a faulty batch of > > > regulators but it is all too easy to blame the component. > > > > > > Thanks for the help > > > > > > > > > Peter > > > >Hi Peter, > > > >I'll assume you have set P2.5 as output and P2Sel.5 as I/O. > > > >Is the port switching from low/hi? > > > >The specs say what you are doing is fine and you have tested regulator > > > >outside of micro so I have no idea. > > > >You say the regulator uses 55uA when enable is low. Doe's this include > >the > > > >micro or just regulator? > > > >If just regulator something is wrong. Are these figures true when you > > > >measure regulator only with enable low then hi? > > > > > > > >good luck, hopefully somebody else can be more helpful > > > > > > > >Dennis > > > >----- Original Message ----- > > > >From: "Peter Grey" <martech@mart...> > > > >To: <msp430@msp4...> > > > >Sent: Tuesday, November 04, 2003 10:53 AM > > > >Subject: Re: [msp430] Problems with switching. > > > > > > > > > > > > > At 09:17 AM 04-11-03 +1300, you wrote: > > > > > > > > > > Hi Dennis, > > > > > > > > > > As in a previous post I should have said FET EMULATION TOOL. > > > > > To avoid problems with my target board I set up the FET to do the > > > >switching > > > > > using a 1121A. When I had the regulator operating alone it was fine. > >When > > > >I > > > > > try and switch power to it using the FET, I get these high currents. > > > > > > > > > > > > > > > all the best > > > > > > > > > > > > > > > Peter > > > > > >Hi Peter, > > > > > >You obviously have something terribly wrong as the regulator is only > > > > > >designed to supply 25mA max. > > > > > >Drop the fet. don't need it as you can switch the enable pin from a > >port > > > > > >directly. In shutdown mode this is only 0.1uA, with pin enabled > >should be > > > > > >250uA. If your application requires low power consumption why not try > >the > > > > > >TPS76933, this has higher shutdown current consumption 1uA but lower > >only > > > > > >17uA quiescent current at full load, though this all depends what > >your > > > >input > > > > > >voltage is as part is a fixed regulator only. Is your hardware clean? > > > >flux > > > > > >residue etc. > > > > > > > > > > > >Dennis > > > > > >----- Original Message ----- > > > > > >From: "Peter Grey" <martech@mart...> > > > > > >To: <msp430@msp4...> > > > > > >Sent: Monday, November 03, 2003 4:50 PM > > > > > >Subject: Re: [msp430] Problems with switching. > > > > > > > > > > > > > > > > > > > I use a MSP430F1121A and it is usually in low current > >applications. I > > > > > > > normally switch power to external chips only when I need them to > > > >conserve > > > > > > > power. However, I now have a problem with this. I have a regulator > > > > > > > (TPS60240) which I provide power to via P2.5. I found the > >regulator > > > >was > > > > > > > drawing too much current in my circuit ( some 25mA with no load on > > > >it.). I > > > > > > > set up the regulator by itself and it draws about 200uA with no > >load > > > >and > > > > > >at > > > > > > > 3.0 volts which is about right. I then use the FET and switch > >power to > > > >the > > > > > > > regulator. When it is not switched high, the current is about 55uA > >and > > > > > >when > > > > > > > I switch it high it is 16.6mA! Again this is with no load. The > > > >TPS60240 > > > > > >has > > > > > > > 2 charge caps (1uF each) and an input and output cap (each 1uF). > > > > > > > Can anyone provide some clues as to what is happening? > > > > > > > > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > > > > > > Peter > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > . > > > > > > > > > > > > > > > > > > > > > > > > > > > > ">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >. > > > > > > > > > > > > > > > > > > > > > > > >">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > > > > > > > > . > > > > > > > > > > > > > > > > > > > > ">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >. > > > > > > > > > > > > > > > >">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > . > > > > > > > > > > > > ">http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > >. > > > > > > > >">http://docs.yahoo.com/info/terms/ > > > > > . > > > > ">http://docs.yahoo.com/info/terms/ > > >
Reply by ●November 4, 20032003-11-04
At 02:51 PM 4/11/2003 +1300, you wrote:
Thanks for all the help Dennis. I will take a look at this one later this
evening.
all the best
Peter
>Hi Peter,
>
>I was just looking thru the data sheets and noticed the part REG710-33.
>0.01uA shutdown mode, 65uA quiescent current when active, 1.8 - 5.5 v input,
>6 pin device. Well worth a look
>
>good luck
>Dennis
>----- Original Message -----
>From: "Peter Grey" <martech@mart...>
>To: <msp430@msp4...>
>Sent: Tuesday, November 04, 2003 1:27 PM
>Subject: Re: [msp430] Problems with switching.
>
>
> > At 01:03 PM 4/11/2003 +1300, you wrote:
> >
> > Hi Dennis,
> >
> > The regulator is used to provide 3.3 volts for a ADXL202 which draws
>0.6mA.
> > I want a stable voltage even if the Li voltage drops below 3 volts. As
the
> > regulator draws 200uA and the sensor 0.6mA the pin P2.5 should be able
to
> > handle this??
> > However, I will set it up as you suggest and see what happens. I
selected
> > this part because of the low current draw and have laid out a board to
> > suit. If I still have problems after all this I will select another
part
> > and start again.
> >
> >
> > Thanks again
> >
> >
> > Peter
> > >Hi Peter,
> > >You shouldn't feed Vin via the P2.5 pin as it's output
current source is
> > >3.4mA with 12mA for all ports combined.
> > >Vin should be connected to Vcc of micro if this micro regulator
permits
>and
> > >drive the enable pin from P2.5 only. You never mentioned you
voltage
>source.
> > >I'll assume it's from 1 x lion cell as that's what
your regulator is
> > >designed for being step up.
> > >The 55uA from regulator only is way off also. Do you have another
part to
> > >try?
> > >Doe's it have to be this part, what are you powering?
> > >Good luck
> > >
> > >Dennis
> > >----- Original Message -----
> > >From: "Peter Grey" <martech@mart...>
> > >To: <msp430@msp4...>
> > >Sent: Tuesday, November 04, 2003 12:11 PM
> > >Subject: Re: [msp430] Problems with switching.
> > >
> > >
> > > > At 11:27 AM 04-11-03 +1300, you wrote:
> > > >
> > > > Hi Dennis
> > > > I have set P2.5 to and output and have not touched P2Sel.5
as it
>should be
> > > > set up as I/O on start up. The port is switching from low to
high. The
> > >55uA
> > > > is from the regulator only which is a little disconcerting
as I would
>not
> > > > expect any current. I have the enable of the regulator wired
to the
>input
> > > > line. That is, I switch both enable and Vin from P2.5.
> > > > If I set up the regulator with enable and Vin common and use
a power
> > >supply
> > > > to switch on these lines all is OK. I will try just
switching the
>enable
> > > > line and see what happens. I am wondering if I have a faulty
batch of
> > > > regulators but it is all too easy to blame the component.
> > > >
> > > > Thanks for the help
> > > >
> > > >
> > > > Peter
> > > > >Hi Peter,
> > > > >I'll assume you have set P2.5 as output and P2Sel.5
as I/O.
> > > > >Is the port switching from low/hi?
> > > > >The specs say what you are doing is fine and you have
tested
>regulator
> > > > >outside of micro so I have no idea.
> > > > >You say the regulator uses 55uA when enable is low.
Doe's this
>include
> > >the
> > > > >micro or just regulator?
> > > > >If just regulator something is wrong. Are these figures
true when you
> > > > >measure regulator only with enable low then hi?
> > > > >
> > > > >good luck, hopefully somebody else can be more helpful
> > > > >
> > > > >Dennis
> > > > >----- Original Message -----
> > > > >From: "Peter Grey" <martech@mart...>
> > > > >To: <msp430@msp4...>
> > > > >Sent: Tuesday, November 04, 2003 10:53 AM
> > > > >Subject: Re: [msp430] Problems with switching.
> > > > >
> > > > >
> > > > > > At 09:17 AM 04-11-03 +1300, you wrote:
> > > > > >
> > > > > > Hi Dennis,
> > > > > >
> > > > > > As in a previous post I should have said FET
EMULATION TOOL.
> > > > > > To avoid problems with my target board I set up
the FET to do the
> > > > >switching
> > > > > > using a 1121A. When I had the regulator operating
alone it was
>fine.
> > >When
> > > > >I
> > > > > > try and switch power to it using the FET, I get
these high
>currents.
> > > > > >
> > > > > >
> > > > > > all the best
> > > > > >
> > > > > >
> > > > > > Peter
> > > > > > >Hi Peter,
> > > > > > >You obviously have something terribly wrong as
the regulator is
>only
> > > > > > >designed to supply 25mA max.
> > > > > > >Drop the fet. don't need it as you can
switch the enable pin from
>a
> > >port
> > > > > > >directly. In shutdown mode this is only 0.1uA,
with pin enabled
> > >should be
> > > > > > >250uA. If your application requires low power
consumption why not
>try
> > >the
> > > > > > >TPS76933, this has higher shutdown current
consumption 1uA but
>lower
> > >only
> > > > > > >17uA quiescent current at full load, though
this all depends what
> > >your
> > > > >input
> > > > > > >voltage is as part is a fixed regulator only.
Is your hardware
>clean?
> > > > >flux
> > > > > > >residue etc.
> > > > > > >
> > > > > > >Dennis
> > > > > > >----- Original Message -----
> > > > > > >From: "Peter Grey"
<martech@mart...>
> > > > > > >To: <msp430@msp4...>
> > > > > > >Sent: Monday, November 03, 2003 4:50 PM
> > > > > > >Subject: Re: [msp430] Problems with switching.
> > > > > > >
> > > > > > >
> > > > > > > > I use a MSP430F1121A and it is usually
in low current
> > >applications. I
> > > > > > > > normally switch power to external chips
only when I need them
>to
> > > > >conserve
> > > > > > > > power. However, I now have a problem
with this. I have a
>regulator
> > > > > > > > (TPS60240) which I provide power to via
P2.5. I found the
> > >regulator
> > > > >was
> > > > > > > > drawing too much current in my circuit (
some 25mA with no
>load on
> > > > >it.). I
> > > > > > > > set up the regulator by itself and it
draws about 200uA with
>no
> > >load
> > > > >and
> > > > > > >at
> > > > > > > > 3.0 volts which is about right. I then
use the FET and switch
> > >power to
> > > > >the
> > > > > > > > regulator. When it is not switched high,
the current is about
>55uA
> > >and
> > > > > > >when
> > > > > > > > I switch it high it is 16.6mA! Again
this is with no load. The
> > > > >TPS60240
> > > > > > >has
> > > > > > > > 2 charge caps (1uF each) and an input
and output cap (each
>1uF).
> > > > > > > > Can anyone provide some clues as to what
is happening?
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks
> > > > > > > >
> > > > > > > >
> > > > > > > > Peter
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > .
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > ">http://docs.yahoo.com/info/terms/
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >">http://docs.yahoo.com/info/terms/
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > .
> > > > > >
> > > > > >
> > > > > >
> > > > > > ">http://docs.yahoo.com/info/terms/
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >.
> > > > >
> > > > >
> > > > >
> > > > >">http://docs.yahoo.com/info/terms/
> > > >
> > > >
> > > >
> > > >
> > > > .
> > > >
> > > >
> > > >
> > > > ">http://docs.yahoo.com/info/terms/
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >.
> > >
> > >
> > >
> > >">http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
> > .
> >
> >
> >
> > ">http://docs.yahoo.com/info/terms/
> >
> >
> >
>
>
>
>
>.
>
>
>
>">http://docs.yahoo.com/info/terms/
Reply by ●November 4, 20032003-11-04
At 11:50 03-11-03 +0800, you wrote:
>I use a MSP430F1121A and it is usually in low
current applications. I
>normally switch power to external chips only when I need them to conserve
>power. However, I now have a problem with this. I have a regulator
>(TPS60240) which I provide power to via P2.5. I found the regulator was
>drawing too much current in my circuit ( some 25mA with no load on it.). I
>set up the regulator by itself and it draws about 200uA with no load and at
>3.0 volts which is about right. I then use the FET and switch power to the
>regulator. When it is not switched high, the current is about 55uA and when
>I switch it high it is 16.6mA! Again this is with no load. The TPS60240 has
>2 charge caps (1uF each) and an input and output cap (each 1uF).
>Can anyone provide some clues as to what is happening?
>
>
>Thanks
>
>
>Peter
I have followed the previous questions and answers on this subject.
There is no reason that you cannot do what you say, and it should work BUT,
since it seems not to work properly for you there are possibly some
"stupid" problems.
You say you are powering the regulator from a pin of the microprocessor.
In principle this is ok. How do you give power to the system?
Since you can measure your current I assume that you are powering the FET
board with some external battery or power supply.
1) How exactly do you set up the whole thing? The battery does power the
FET board as well? Or the Fet board is powered from the JTAG?
2) The current you measure is the total current from the battery? Or is it
really the measured current into the supply pin of the regulator (TPS...)?
3) Do you measure the total current while the Jtag interface is connected?
regards
A.Morra
Reply by ●November 4, 20032003-11-04
The equivalent circuit you describe is similar to placing a large (1uF)
capacitance directly on the MSP430 output pin. In essence you can't do this
without stressing the MSP430 device and possibly introducing latch-up problems.
You might try a series isolation resistor attached directly to the MSP430 pin
so that current to the regulator flows through the resistor; ideally this
resistor should be defined by the supply voltage divided by the maximum current
the pin will output. I don't have your data sheet to hand but typically you
can
steal from the MSP430 output pin 1.5mA for a voltage drop of 0.25V from the
supply. (3.3-0.25)V/1.5mA = 2K. This is a safe value, but you could go lower.
You can't go to 0R.
Here's a random tip: short two output pins together and drive in opposite
directions (as in spurious solder blobs). Can produce some unexpected
power-on-resets.
Hope this helps.
Hugh
--- Peter Grey <martech@mart...> wrote:
> I use a MSP430F1121A and it is usually in low
current applications. I
> normally switch power to external chips only when I need them to conserve
> power. However, I now have a problem with this. I have a regulator
> (TPS60240) which I provide power to via P2.5. I found the regulator was
> drawing too much current in my circuit ( some 25mA with no load on it.). I
> set up the regulator by itself and it draws about 200uA with no load and at
> 3.0 volts which is about right. I then use the FET and switch power to the
> regulator. When it is not switched high, the current is about 55uA and when
> I switch it high it is 16.6mA! Again this is with no load. The TPS60240 has
> 2 charge caps (1uF each) and an input and output cap (each 1uF).
> Can anyone provide some clues as to what is happening?
>
>
> Thanks
>
>
> Peter
>
>
>
__________________________________
Reply by ●November 4, 20032003-11-04
Why not use something like the MAX4626 power switch? This is useful
where you need to control several tens of milliamps to several devices
and have the required voltage levels available. Alternatively I often
power sensors directly from the MSP430 I/O pins (after filtering of
course). Finally if you must use a regulator or converter pick one witha
SHDN (Shutdown) pin. These are common, and allow a digital signal to
turn off the regulato. many of these have current draws as low as 0.1uA
in shutdown mode.
Al
Peter Grey wrote:
> I use a MSP430F1121A and it is usually in low
current applications. I
> normally switch power to external chips only when I need them to conserve
> power. However, I now have a problem with this. I have a regulator
> (TPS60240) which I provide power to via P2.5. I found the regulator was
> drawing too much current in my circuit ( some 25mA with no load on it.). I
> set up the regulator by itself and it draws about 200uA with no load and at
> 3.0 volts which is about right. I then use the FET and switch power to the
> regulator. When it is not switched high, the current is about 55uA and when
> I switch it high it is 16.6mA! Again this is with no load. The TPS60240 has
> 2 charge caps (1uF each) and an input and output cap (each 1uF).
> Can anyone provide some clues as to what is happening?
>
>
> Thanks
>
>
> Peter
>
>
>
>
> .
>
>
>
> ">http://docs.yahoo.com/info/terms/
>
>
>
Reply by ●November 4, 20032003-11-04
At 02:45 PM 04-11-03 +0100, you wrote:
>At 11:50 03-11-03 +0800, you wrote:
> >I use a MSP430F1121A and it is usually in low current applications. I
> >normally switch power to external chips only when I need them to
conserve
> >power. However, I now have a problem with this. I have a regulator
> >(TPS60240) which I provide power to via P2.5. I found the regulator was
> >drawing too much current in my circuit ( some 25mA with no load on
it.). I
> >set up the regulator by itself and it draws about 200uA with no load
and at
> >3.0 volts which is about right. I then use the FET and switch power to
the
> >regulator. When it is not switched high, the current is about 55uA and
when
> >I switch it high it is 16.6mA! Again this is with no load. The TPS60240
has
> >2 charge caps (1uF each) and an input and output cap (each 1uF).
> >Can anyone provide some clues as to what is happening?
> >
> >
> >Thanks
> >
> >
> >Peter
>
>I have followed the previous questions and answers on this subject.
>There is no reason that you cannot do what you say, and it should work BUT,
>since it seems not to work properly for you there are possibly some
>"stupid" problems.
>
>You say you are powering the regulator from a pin of the microprocessor.
>In principle this is ok. How do you give power to the system?
>Since you can measure your current I assume that you are powering the FET
>board with some external battery or power supply.
>1) How exactly do you set up the whole thing? The battery does power the
>FET board as well? Or the Fet board is powered from the JTAG?
>2) The current you measure is the total current from the battery? Or is it
>really the measured current into the supply pin of the regulator (TPS...)?
>3) Do you measure the total current while the Jtag interface is connected?
>
>regards
>A.Morra
I have the FET board connected to my laptop. I then run 2 wires from the
IDC connectors on the FET board (ground and P2.5). The ground goes directly
on the chip and the P2.5 goes through a current meter and then onto the Vcc
and enable lines.
The current is that drawn by the chip, ie as per the setup above.
Yes the JATG is connected
An email from Hugh may be my answer. I will be setting up the chip with Vcc
connected to the chip and the MSP430 only using the enable line.
Thanks for the help
Peter
Reply by ●November 4, 20032003-11-04
At 07:53 AM 04-11-03 -0800, you wrote:
This now sounds like my problem. It is so easy when you see it!! I will
drive the enable line only which is what I should have done in the first
place. It was force of habit as I drive a lot of external chips by the Vcc
line but in the past they all have only had a 0.1uF cap on the line.
Thanks Hugh
Peter
>The equivalent circuit you describe is similar to
placing a large (1uF)
>capacitance directly on the MSP430 output pin. In essence you can't do
this
>without stressing the MSP430 device and possibly introducing latch-up
>problems.
>You might try a series isolation resistor attached directly to the MSP430
pin
>so that current to the regulator flows through the resistor; ideally this
>resistor should be defined by the supply voltage divided by the maximum
>current
>the pin will output. I don't have your data sheet to hand but typically
>you can
>steal from the MSP430 output pin 1.5mA for a voltage drop of 0.25V from the
>supply. (3.3-0.25)V/1.5mA = 2K. This is a safe value, but you could go
lower.
>You can't go to 0R.
>
>Here's a random tip: short two output pins together and drive in
opposite
>directions (as in spurious solder blobs). Can produce some unexpected
>power-on-resets.
>
>Hope this helps.
>Hugh
>
>--- Peter Grey <martech@mart...> wrote:
> > I use a MSP430F1121A and it is usually in low current applications. I
> > normally switch power to external chips only when I need them to
conserve
> > power. However, I now have a problem with this. I have a regulator
> > (TPS60240) which I provide power to via P2.5. I found the regulator
was
> > drawing too much current in my circuit ( some 25mA with no load on
it.). I
> > set up the regulator by itself and it draws about 200uA with no load
> and at
> > 3.0 volts which is about right. I then use the FET and switch power to
the
> > regulator. When it is not switched high, the current is about 55uA and
> when
> > I switch it high it is 16.6mA! Again this is with no load. The
TPS60240
> has
> > 2 charge caps (1uF each) and an input and output cap (each 1uF).
> > Can anyone provide some clues as to what is happening?
> >
> >
> > Thanks
> >
> >
> > Peter
> >
> >
> >
>
>
>__________________________________
>
>
>
>.
>
>
>
>">http://docs.yahoo.com/info/terms/
