Using DTR for Vpp

[ghamel]

Posted on June 27, 2003 at 15:00

Using DTR for Vpp

[ghamel]

Posted on June 24, 2003 at 18:17

My ST7 application needs to be reprogrammed via RS232 and a PC. (using a Maxim MAX3323E). I am looking at ways to get the 11.4-12.6V Vpp. I was thinking about using DTR (Data Terminal Ready) from the PC as a programming voltage. (using a schottky diode to block -12 when DTR=''0''.

I don't know what the expected range of the 12V power supply in PCs and laptops might be and whether this might work. Has anyone tried this?

[simonharrison9]

Posted on June 25, 2003 at 07:00

Hi,

Typically, serial port levels are lower than you require. Could you toggle the DTR quite quickly? If you could, a simple voltage doubler circuit may work - (2 caps, 2 diodes) with a zener to clamp the maximum voltage. Regards, Simon [ This message was edited by: sjh on 12-11-2003 16:22 ]

[ghamel]

Posted on June 27, 2003 at 15:00

I decided to use DTR to enable a ST662A charge pump via a transistor buffer. I am building up a breadboard and will test it.