| Electronics > Projects, Designs, and Technical Stuff |
| A problem about check if my PSU work?(Use PC817) |
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| China NewBoy:
i have made a switching-mode power and i want my Atmega16 read if my power work , in the current scheme,i use the optocoupler pc817 which is connect to the PWM chip(ob2269)’s Vdd. but, i meet some problems , when the PC817 is connected to the VCC,the PWM chip dont work at all,because its Vin stay at 4.7V (the typical work volt is 19V). if the PC817 is NOT connected, i found the PSU work. i wonder what caused this problem. Here ↓ is my scheme pdf and some printscreen pics |
| xavier60:
The startup current is very low. Vdd must have no load on it to start. Does the opto need to be driven from the primary side? |
| China NewBoy:
--- Quote from: xavier60 on November 08, 2019, 02:35:08 am ---The startup current is very low. Vdd must have no load on it to start. Does the opto need to be driven from the primary side? --- End quote --- im considering put my opto on the secondary side , i will do some experiments on the breadboard to figure out if it can work on secondary side here ↓ is my new plan |
| China NewBoy:
--- Quote from: China NewBoy on November 08, 2019, 02:45:45 am --- --- Quote from: xavier60 on November 08, 2019, 02:35:08 am ---The startup current is very low. Vdd must have no load on it to start. Does the opto need to be driven from the primary side? --- End quote --- im considering put my opto on the secondary side , i will do some experiments on the breadboard to figure out if it can work on secondary side here ↓ is my new plan --- End quote --- it can work on the secondary side now! ;D ;D ;D but im still wondering ,why adding load to VDD could impact the volt of Vin? |
| xavier60:
Before the power supply starts, the only available current is via the VIN pin. |
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