AC spike go pass XFRM and regulator to reset CPU!!??

Started by Rodo in comp.arch.embedded12 years ago 9 replies

Hi all, I have a device that is powered by 240VAC (also works from 120VAC). The AC drives the primary of a transformer (with a fuse and a...

Hi all, I have a device that is powered by 240VAC (also works from 120VAC). The AC drives the primary of a transformer (with a fuse and a MOV). There is also a fan connected to the 240VAC with a switch. The secondary of the transformer has a bridge, a large electrolytic cap (1000uF/25v) and an LM7805 regulator. There is a smaller cap (10uF/10v and 01uF/25v) at the output of the LM7805. ...


voltage regulator configuration

Started by kalyanamsaritha in comp.arch.embedded12 years ago 3 replies

Hi, I have a power requirement for +5V, +3.3V and +1.8V. Studying available designs, I have seen both parallel and...

Hi, I have a power requirement for +5V, +3.3V and +1.8V. Studying available designs, I have seen both parallel and series configuration. 1. Series +5V DC input with voltage regulators connected in series to convert +5V to +3.3V, and +3.3V to +1.8V 2. Parallel +5V DC input to +3.3V output, and +5V DC input to +1.8V output. In both cases, all three voltages are available. Wha...


AC spike go pass XFRM and regulator to reset CPU [Part 2]: It is irradiated?

Started by Rodo in comp.arch.embedded12 years ago 3 replies

Hi all, A while back I posted a problem I was having with a spike (see original text below). Someone suggested that the spike would be in the...

Hi all, A while back I posted a problem I was having with a spike (see original text below). Someone suggested that the spike would be in the ground line as well. So I connected the scope probe and ground to the ground of the circuit and yeap, there it was. I felt rather silly connecting the scope probe and ground together but oh well ... This week I disconnected the probe but left it ...


Shelf life of solder

Started by Andrew Smallshaw in comp.arch.embedded11 years ago 9 replies

Managed to fry a voltage regulator earlier today attempting to solder it in place. It just wasn't wetting properly and when I came to test it...

Managed to fry a voltage regulator earlier today attempting to solder it in place. It just wasn't wetting properly and when I came to test it was well off the correct voltage - I noticed it had got a little warm when working on it. Now cooking a 7805 is no big deal in itself - after all they cost approximately nothing - but it could just as easily have been a more interesting component. I'...


Constant Current Regulators ('diodes') are back

Started by -jg in comp.arch.embedded11 years ago 2 replies

On Semi have released some low cost, constant current regulators that target LED drive, but have many more...

On Semi have released some low cost, constant current regulators that target LED drive, but have many more applications http://www.onsemi.com/PowerSolutions/newsItem.do?article=2094 Starting at $0.0545/10K, these are not the usual 'niche price nonsense' seen on other current regulator 2 terminal devices 'diodes'. Right now in 20/25/30mA, hopefully they can do 5/10/15mA too, soon... ...


Cypress Add Turbo 8051 to PSoC (and Cortex too)

Started by -jg in comp.arch.embedded11 years ago

Cypress cover BOTH bases, in a move that has to get everyone's attention ! - Single clock 8051 16/32/64KF, up to 8KR, with up to 67MHz...

Cypress cover BOTH bases, in a move that has to get everyone's attention ! - Single clock 8051 16/32/64KF, up to 8KR, with up to 67MHz operation, and 120 part numbers Wide 1.7-5.5V operation.. LCD drive, 0.5V boost regulator... 0.1% voltage reference (14 ppm/=B0C) optional 24bx24b MAC - Cortex parts are 32K-256KF, and up to 64KRam, and 5.5V IO's well... (but no 32 bit timers?) Choic...


need advice on device design

Started by emanuel_ovidiu in comp.arch.embedded10 years ago 4 replies

For my bachelor project i need a device capable of collecting data from sensors and transmit it through a 802.11b transceiver to a pc. I've...

For my bachelor project i need a device capable of collecting data from sensors and transmit it through a 802.11b transceiver to a pc. I've worked until now only with software high and low-end programming but never with hardware ; I've started reading and looking through tons of stuff but I failed at finding a small factor , max 5cm x 5cm board with an mcu , power regulator (as the device has to ...


Servo resets demo board

Started by Joel in comp.arch.embedded10 years ago 4 replies

I attempted to piece together a system composed of a sensor, continuous rotation servo from Parallax and a Dragon12 plus hcs12 demo board in...

I attempted to piece together a system composed of a sensor, continuous rotation servo from Parallax and a Dragon12 plus hcs12 demo board in order to test a control algorithm. The problem is that sometimes when the program gets to a point where the servo control signal changes, the whole board resets. The servo runs on its own regulator so I don't think its a power issue. Why does running the s...


PCB grounding

Started by abrous in comp.arch.embedded10 years ago 1 reply

Hi to all, I am designing a PCB with a digital circuit based on a STM32F103 MCU with USB,LAN and RS232 ports. The power comes from an external...

Hi to all, I am designing a PCB with a digital circuit based on a STM32F103 MCU with USB,LAN and RS232 ports. The power comes from an external wall type 12V/2.5A switching type regulator. There are 3 grounds in my PCB : a digital ground (GND), a connector frame ground (FGND) which is connected to GND through a 3.9nF/1KV capacitor and the input ground (the common which comes from the external po...


1V regulator run from a single NiMH battery

Started by Anonymous in comp.arch.embedded9 years ago 6 replies

I need to supply a 1V to a the real time clock section of a Atmel AT91SAM9G20 at 9uA. This has a min input of 0.9V and a max of 1.1. I would...

I need to supply a 1V to a the real time clock section of a Atmel AT91SAM9G20 at 9uA. This has a min input of 0.9V and a max of 1.1. I would like to use a single NiMH battery which has a max output of 1.4V. My problem is that most linear regulators use a 1.23V reference so I am not sure what happens to the output voltage when the battery voltage drops to 1.2V. Can anybody offer any advice or ...


PID controller, help

Started by Lox in comp.arch.embedded8 years ago 4 replies

Hello all I'm trying to implement a PIC controller to controll the position by adjusting the speed of an motor. The input I have is the...

Hello all I'm trying to implement a PIC controller to controll the position by adjusting the speed of an motor. The input I have is the position. My colleague says that I first must derivate the position and use it as input to the PID regulator. Do I have to do that? He says I must have speed as an input because I have speed as an output!?!?!?! That sounds strange.


Preferred LiFePO4 USB charger/regulator IC

Started by Clifford Heath in comp.arch.embedded7 years ago 22 replies

I'm building some hand-held gear with STM32 and other stuff on a 3.2V supply, with consumption up to a watt or two, and want to use a single...

I'm building some hand-held gear with STM32 and other stuff on a 3.2V supply, with consumption up to a watt or two, and want to use a single LiFePO4 cell with USB charging, and preferably just run directly off Vbatt, with no additional regulator. The Linear LTC4098 looks nice, and Maxim has the MCP73833. Any experience using these, or alternatives to suggest? Hand-solderable would be ...


Ambiq "Ultra" Low Power ARM MCUs

Started by rickman in comp.arch.embedded4 years ago 4 replies

This part seems to have extremely low power consumption compared to other CM4 devices. They cite 34 uA/MHz using built in buck regulators...

This part seems to have extremely low power consumption compared to other CM4 devices. They cite 34 uA/MHz using built in buck regulators with inductors that appear to be about 0603 size. When running from 1.8 volts the current is specified as 51 uA/MHz when I assume the buck regulators aren't running or maybe they give less advantage. The down side seems to be the part only runs at 2...


Free through-hole parts to good home

Started by larwe in comp.arch.embedded14 years ago 4 replies

I am taking the remainder of my through-hole parts collection and dumping it in a box. I haven't built a through-hole prototype or reworked a...

I am taking the remainder of my through-hole parts collection and dumping it in a box. I haven't built a through-hole prototype or reworked a through-hole board in I don't know how long, and this stuff is wasting shelf space. (My proto kit containing every single 0603 value I need in resistors and ceramic caps, plus all my SOT23 transistors and regulators, fits in a few hundred 1-dram samp...


High Vin LDO with truely low dropout in small package (long post)

Started by rickman in comp.arch.embedded14 years ago 55 replies

We often need to power low current circuits (

We often need to power low current circuits (


peculiar input current problem

Started by abq_guy in comp.arch.embedded11 years ago 3 replies

Hello, I am using a DC-DC converter from DATEL ( BWR-15/670-D12A). The inputs are +15V and the outputs are +15V and -15V. The converter can...

Hello, I am using a DC-DC converter from DATEL ( BWR-15/670-D12A). The inputs are +15V and the outputs are +15V and -15V. The converter can give upto 670mA of output current on both +15V and -15V individually. I am using these output voltages to power 2 Linear LDO regulators (LT1962 and LT1964). These regulators take in the +15V and the -15V from the DC-DC converter and convert them to +14.8...


Switchers

Started by Vladimir Vassilevsky in comp.arch.embedded9 years ago 2 replies

It turns out that switching regulators can generate significant ripple at the output for the brief moment when the external sync signal is...

It turns out that switching regulators can generate significant ripple at the output for the brief moment when the external sync signal is applied or removed. Sometimes that caused mysterios result which was very difficult to trace to the cause. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com


Synchronising two voltage regulators

Started by Simon in comp.arch.embedded8 years ago 11 replies

So, I have a power headache :) One of the chips I want to use in a project has very specific power requirements ... - The VDD supply must...

So, I have a power headache :) One of the chips I want to use in a project has very specific power requirements ... - The VDD supply must ramp from 0V to its final value within 10ms to ensure correct startup. - The IO VDD supply must ramp to its final value before VDD reaches 0.4 V. - The power supplies must be brought up monotonically - (other stuff that's not so relevant)


Q wrt Bluetooth, USB, RS232 and controllers

Started by bit eimer in comp.arch.embedded16 years ago 10 replies

Hi all, I'm new to this forum - hope to find some answers/help on the following: I doing a project in which a laptop needs to communicate...

Hi all, I'm new to this forum - hope to find some answers/help on the following: I doing a project in which a laptop needs to communicate with a remote PIC-based device. I had originally planned to use RS232 at each end talking through a pair of 900 MHz Linx transceivers. Since this was to be a one-off prototype, I kind of ignored the regulatory issues. Now, I'm thinking that maybe I...


Bluetooth pairing + FDA

Started by dutchman in comp.arch.embedded13 years ago

I am using some Bluetooth modules and it is important that the devices are paired uniquely. The product needs to meet all the...

I am using some Bluetooth modules and it is important that the devices are paired uniquely. The product needs to meet all the regulatory requirements for the FDA and I was told by a friend that they will not allow pairing of devices based off a software key. My understanding was that there had to be a hardware key (dongle, sdcard) or something on the device to be sure there are not mistakes...