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Status report on project requirements

A project log for Low-Cost Programmable Power Supply

Chinese "LM2596 DC/DC buck converter with voltmeter" + "some wires" + "Forth" = "programmable power supply"

thomasThomas 01/30/2017 at 10:550 Comments

It's time for a status report :-)


Requirement Status Comment
remote control through serial interface for multiple coordinated power supplies Remote control works The requirements for "multiple coordinated power supplies" must be refined.
EDIT: a 100nF bypass ceramics capacitor between GND and pin 2 of the LM317 must be retrofitted. Otherwise the serial communication won't work.
programmable on/off and at least two fixed voltage levels, optionally programmable output voltage I can control on/off and two voltage levels with OUT! I left the LED connected to PB4, but I'm not happy with the LED current. A damaged LED isn't the issue but the accuracy impact on STM8S analog inputs is. Removing the LED is a possible solution. Other option: use a blue or white LED instead of red,
Changing the output voltage a with resistor connecting the LM2596 feedback loop and PC.3 (former LED in) works.
2 out! \ enable LM2596, 1st level
3 out! \ enable LM2596, 2nd level
0 out! \ disable LM2596


monitoring of output voltage, and optionally output current ain4= Vout * 18.4/V
The resolution is about 54mV/digit, and there is just enough noise for some averaging. The resolution is sufficiently low for a range of about 56V. Great job guys ;-)
optionally measurement input voltage ain2 = Vin * 18.4/V Same as Vout
To show it on the LED display I used this snippet:
: Vin 2 adc! adc@ 100 * 184 / . ;
' Vin bg ! \ run Vin in background
7S-LED status display works Segment DP is currently shared with the serial interface. I'd like to improve method for limiting the duty cycle
price per unit < $3 (excluding the external power source) $1.51 + 1 x C 100nF + 10 cm wire + some SnPb 3 more modules ordered for $1.48/pcs



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