very low power DC-(HV)DC converter - Page 1
Forum section: electronics / projects

author: sdouble
author_rank: Frequent Contributor
timestamp: September 06, 2017, 10:14:11 pm
content: hi guys,I try to develop a micro-power +5V to +-200V (positive and negative, 2 designs needed)My constraints are the following :1) minimize EMC : I have sensitive equipments around2) little space available (30 x 20 mm2 at best) on the PCB3) ripple < 15 mv p-p4) low power consumption 75mW at most, target is 50 mWthe load is negligible : less than 1 micro Amp.any advice about the most suitable circuit topology ?thanks

author: Marco
author_rank: Super Contributor
timestamp: September 07, 2017, 07:17:31 am
content: Use a small xenon trigger transformer? Given the power requirements you can afford to be a bit sloppy, feed it a (low passed) square wave through a current limiting resistor, clamp the output with a TVS and linear regulate it with an opamp plus a couple bjts.

author: Zero999
author_rank: Super Contributor
timestamp: September 07, 2017, 08:14:05 am
content: An electroluminescent lamp driver IC? A rectifier/voltage doubler could be used to create the -200VDC.https://www.rogerscorp.com/documents/25/durel/DUREL-D305A-EL-Lamp-Driver.pdfhttp://www.mouser.com/ds/2/391/HV857L-14900.pdfhttps://www.monolithicpower.com/DesktopModules/DocumentManage/API/Document/GetDocument?id=1769

author: sdouble
author_rank: Frequent Contributor
timestamp: September 07, 2017, 07:40:49 pm
content: too many options guys !thanks a lot for your suggestions.I'm after very low EMI. Hard switching is not an option due to that issue.

author: sdouble
author_rank: Frequent Contributor
timestamp: September 07, 2017, 08:40:46 pm
content: blueskull,thanks for your suggestions.

author: Zero999
author_rank: Super Contributor
timestamp: September 07, 2017, 08:52:38 pm
content: I found some charge pump based electroluminescent lamp driver ICs. They should produce less EMI than the ones which require an inductor. The peak output voltage is specified at around 80V, with a 3V supply. It should be higher with 5V input. Another diode+capacitor voltage doubler could be used to make +/-200V.http://ww1.microchip.com/downloads/en/DeviceDoc/hv853.pdfhttp://www.mouser.com/ds/2/268/hv852-1022107.pdf

author: daqq
author_rank: Super Contributor
timestamp: September 07, 2017, 08:56:52 pm
content: If you'd like a module:http://uk.farnell.com/w/c/power-line-protection/power-supplies/dc-dc-converters/proportional-high-voltage-converters-dc-dc?product-range=a-seriesDoes the converter need to be isolated? Perhaps you could use a simple step up converter and feed a voltage multiplier and inverter with that? Maybe you could look into piezoelectric transformers?

author: Zero999
author_rank: Super Contributor
timestamp: September 07, 2017, 09:11:43 pm
content: Quote from: daqq on September 07, 2017, 08:56:52 pmThose modules are nice but they're expensive though.Does it need any voltage regulation? If the answer is no and isolation is required, a simple transformer driver IC can be used.http://www.ti.com/lit/ds/symlink/sn6501.pdf

author: sdouble
author_rank: Frequent Contributor
timestamp: September 07, 2017, 09:31:56 pm
content: price is not a major issue here ( in that range). what i like with the modules is that they include a hopefully efficien EMI shielding

author: eliocor
author_rank: Unknown
timestamp: September 08, 2017, 04:41:06 am
content: I suggest you to read Linear Application Note 118:http://www.linear.com/designtools/app_notes.php