Post Date : Mar 09, 2023 / Last updated : Apr 06, 2023

CL discharge (discharge function) is a function that rapidly discharges to capacitance charge connected to the output line during standby. TOREX these are called the CL discharge and CL discharge function, and they are also called by other names, such as discharge function and auto discharge function.

Without a CL discharge function, it is now possible to draw out the output capacitance load during standby, which causes the output voltage to gradually decrease. If the output voltage gradually decreases, it could cause downstream devices to malfunction.

In addition, a power-down sequence may be required by FPGA and other devices. In this case, a CL discharge function is used to quickly power down the output voltage when the power supply sequence is satisfied, so the product must be designed to follow the power-down sequence.

Without CL discharge: XC6221A
With CL discharge: XC6221B

In addition, in some applications the CL discharge function is a demerit.
For applications where an external voltage is applied from the DC/DC or LDO output side using an OR connection, the CL discharge function activates to allow the current to be continuously drawn from the output side.

Caution is required because this not only uses the extra quiescent current from the external power supply but could also cause characteristic degradation to occur in the internal elements that conduct the CL discharge.

Example where the CL discharge function has a negative impact when OR connected