Failsafe capacitor auto-discharge module

This failsafe module will automatically discharge a high-voltage capacitor once the circuit input VCC is removed.

It acts as a solid-state relay with integrated high-power resistors, safely discharging the capacitor's stored energy.

• VCC input (low voltage side): 3.3v-12v 25mA
• High-voltage side: 800v max.
• Opto-isolated low side supply
• LED indicator onboard.

Connect the low voltage input of this module to your charging circuit VCC for example (3.3v-12v),
the HV- pad to the capacitor negative, the HV+ pad to the capacitor positive terminal.

The HV side is galvanically isolated from the VCC input. Both common ground, and separate ground circuits can be used.

Operation mode

• VCC Powered - the HV side will act like an open switch, applying minimal load (3MΩ) to the capacitor to allow normal operation.
  
  
• VCC Removed - the HV side will drain the connected capacitor into the integrated power resistors and safely discharge it
  A red LED will be illuminated during this condition, dimming as the capacitor is discharging, until it is fully discharged (down to about 3v).

*NOTES:
LED on = VCC Removed AND voltage is present on the HV capacitor.
NOT to be used as a measurement or validation method.
ALWAYS DOUBLE CHECK HAZARDOUS VOLTAGE PRESENCE USING A RELIABLE TOOL.