Power Supply Sequence Specification②: Example of Actual Operations

In the previous article, an actual circuit example and component value calculations to make various settings for the power supply sequence specification ② were explained. Here, actual operations of the circuit are confirmed.

Power Supply Sequence Specification②: Example of Actual Operations

The circuit below is an example circuit implementing the power supply sequence ② described in the previous article. It is provided again for confirmation of the circuit operations.

Example of a circuit to realize the power supply sequence ②

The power supply sequence ② operation waveforms are shown below.

Shutoff is performed in the same order as startup, starting from V_OUT1.

When Enable is set to “L” level, DCDC 1 is directly disabled and turned off, and simultaneously the discharge circuit turns on, and V_OUT1 is drawn down to near ground level in the programmed time period.

When V_OUT1 falls below 0.5 V, which is the threshold of the Power Good block IC1, the IC1 OUT output disables DCDC 2, and similarly the discharge circuit turns on and V_OUT2 is drawn down.

When V_OUT2 falls below 0.5 V, which is the threshold of the Power Good block IC2, as in the previous stage, the IC2 OUT output disables DCDC 3, the discharge circuit turns on, and V_OUT3 is drawn down.

With this, all three shutoff sequences end, and all outputs are turned off.