I've been working on this very confusing problem regarding making a TLP152 opto-isolator to work as intended. Here is my circuit using a TLP152 to work as a IGBT gate driver. TLP152 circuit diagram

TLP152 circuit

No matter which way I try, i can't just have any signal at TLP152 output (pin 5). Ways I have tried: using signals ranging from 100 Hz to 50 kHz at 5V peak voltage, leave the LED of TLP152 on (no pwm signal), change TLP152's LED input resistor from 330 Ohm to 220 Ohm. Do you guys have any suggestion on how to make this thing work.

P.S: I have made a similiar circuit using TLP250 and it works, while using TLP152 won't.

  • \$\begingroup\$ Pin 4 is ground \$\endgroup\$ – Marla Dec 29 '15 at 2:47
  • \$\begingroup\$ I'm sorry for using wrong pin number. I meant pin 5 as you pointed out. \$\endgroup\$ – Trần Hữu Đăng Khoa Dec 29 '15 at 3:22
  • \$\begingroup\$ Confirm that you have LED current by checking voltage drop across 330 ohm resistor. \$\endgroup\$ – Marla Dec 29 '15 at 3:29
  • \$\begingroup\$ If you have LED current and have applied appropriate voltage to pin 6, and still doesn't work, then the opto must be bad. \$\endgroup\$ – Marla Dec 29 '15 at 3:37
  • \$\begingroup\$ In case p1R = 330 Ohm resistor, voltage drop across it is 2.978 V. Total voltage drop across p1R and opto's LED is 4.51 V In case p1R = 220 Ohm resistor, voltage drop across it is 2.729 V. Total voltage drop across p1R and opto's LED is 4.29 V My MCU (30f5013) VCC voltage is 5.01 V and its sourcing capacity is 25 mA. So I think in case p1R = 220 Ohm, there's enough current going through opto's LED (TLP152 datasheet recommended current for its LED is from 10mA to 15 mA). \$\endgroup\$ – Trần Hữu Đăng Khoa Dec 29 '15 at 4:35

After your comment where you mention that you are using 5 volts for the driver side of the opto, there is the problem.

The data sheet, in Section 9 states that Vcc minimum is 10 volts and maximum of 30 volts. You need to use higher applied voltage.

enter image description here

  • \$\begingroup\$ It finally worked thanks to your comment! I have made a basic mistake which took me 3 days to solve its problem. Thank you very much. \$\endgroup\$ – Trần Hữu Đăng Khoa Dec 29 '15 at 6:39
  • \$\begingroup\$ By the way, I have upvoted your comment but it won't display for now because I lack reputation. \$\endgroup\$ – Trần Hữu Đăng Khoa Dec 29 '15 at 6:40

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