TIME SEQUENCE CIRCUIT FOR POWER SUPPLY UNIT

摘要

A time sequencing circuit for a power supply unit to ensure the correct sequencing of system voltages for a computer from a power supply unit includes first to fifth resistors, an electronic switch, first to third comparators, and a capacitor. Each of the first to third comparators includes an inverting input terminal, a non-inverting input terminal, and an output terminal When the power supply unit outputs all required voltages, the power supply unit outputs a high-voltage level indicating power good and the computer can start up power good signal. If one of the voltages is not outputted, the power supply unit outputs a low-voltage level good signal until any non-output of voltage is cured.

主权项

1. A time sequence circuit, comprising:
A first to fifth resistor; an electronic switch comprising a first terminal, a second terminal, and a third terminal; a capacitor; and a first to third comparator each comprising an inverting input terminal, a non-inverting input terminal, a power terminal, a ground terminal, and an output terminal; wherein the inverting input terminal of the first comparator is coupled to a first power terminal through the first resistor, and is connected to ground through the second resistor, the non-inverting input terminal of the first comparator is coupled to a second power terminal, the power terminal of the first comparator is coupled to the first power terminal, the ground terminal of the first comparator is connected to ground, and the output terminal of the first comparator is coupled to the second power terminal through the third resistor, and is connected to ground through the capacitor; the inverting input terminal of the second comparator is coupled to the first power terminal through the fourth resistor, and is connected to ground through the fifth resistor, the non-inverting input terminal of the second comparator is coupled to a third power terminal, the power terminal of the second comparator is coupled to the first power terminal, the ground terminal of the second comparator is connected to ground, and the output terminal of the second comparator is coupled to the output terminal of the first comparator; the inverting input terminal of the third comparator is coupled to the first power terminal, the non-inverting input terminal of the third comparator is coupled to a fourth power terminal, the power terminal of the third comparator is coupled to the first power terminal, the ground terminal of the third comparator is connected to ground, and the output terminal of the third comparator is coupled to the output terminal of the first comparator; the first terminal of the electronic switch is used to receive a power on signal, the second terminal of the electronic switch is connected to ground, the third terminal of the electronic switch is coupled to the output terminal of the first comparator, and the output terminal of the first comparator outputs a power good signal; when the first terminal of the first electronic switch is at a low-voltage level, the second and third terminals of the electronic switch are disconnected from each other; when the first terminal of the first electronic switch is at a high-voltage level, the second and third terminals of the electronic switch are connected to each other.