Circuits to Implement Power Supply Sequences Using General-Purpose Power Supply ICs　ーSummaryー

Key Points of This Article

・For ICs and electronic equipment requiring multiple power supplies, in some cases ordered turn-on and turn-off, or sequence control, is needed.

・In these articles, examples are presented in which general-purpose power supplies and external circuits are used to implement sequence control, without using sequence control ICs or power supply ICs with sequence support functions.

Key Points of This Article

・In sequence ①, power supplies with three supply voltages are turned on in order, and are shut off in the reverse order.

・For design purposes, the function blocks needed to obtain the target operations are considered.

・To achieve sequence ①, three DCDC ICs, four Power Good circuits, and three discharge circuits are used.

Key Points of This Article

・In Sequence ①, power supplies with three supply voltages are turned on in order, and are shut off in the reverse order.

・In order to aid understanding of the sequence operation, the operations for turn-on of the three power supply systems were presented separately.

Key Points of This Article

・In sequence ①, power supplies with three supply voltages are turned on in order, and shut off in the reverse order.

・In order to facilitate understanding of sequence operations, the operations at power shutoff for each of the three power supply systems were illustrated in terms of three stages.

Key Points of This Article

・A circuit to realize the power supply sequence ① consists of 3 DCDC ICs, 4 Power Good circuits, 3 discharge circuits, and diodes.

Key Points of This Article

・Confirm the specifications, circuit operations, and waveforms for power supply sequence ①.

Key Points of This Article

・The specifications of the power supply sequence ② are confirmed.

・A function block diagram to represent the specifications is created.

Key Points of This Article

・In sequence ②, three power supply systems are turned on in order, and are shut off in the same order.

・In order to aid understanding of sequence operation, the operation at the time of turn-on of each of the three power supply systems is shown separately.

Key Points of This Article

・In sequence ②, three power supply systems are turned on in order, and are shut off in the same order.

・In order to aid understanding of sequence operation, the operation at the time of shutoff of each of the three power supply systems is shown separately.

Key Points of This Article

・A circuit to realize the power supply sequence ② consists of 3 DCDC ICs, 2 Power Good circuits, and 3 discharge circuits.

Key Points of This Article

・The power supply sequence ② specifications, circuit operation, and waveforms are confirmed