Power-good signal generator and controller with power sequencing free

摘要

A power-good signal generator generates a power-good signal according to a control signal of a controller, and comprises an impedance element, a controlled transistor and a power sequencing free circuit. An end of the impedance element is coupled to a second voltage source. The controlled transistor has first and second input/output ends and a controlled end, wherein the first input/output end is coupled to the other end of the impedance element to generate the power-good signal. An operating state of the controlled transistor is changed in response to the control signal. The power sequencing free circuit is coupled to the controlled end and one of the first input/output end and the second voltage source. When the second voltage source is supplied before the first voltage source, the power sequencing free circuit turns on the controlled transistor to clamp the power-good signal to be lower than a predetermined voltage level.

主权项

1. A power-good signal generator with power sequencing free for generating a power-good signal according to a control signal of a controller, wherein an input power terminal of the controller is coupled to a first voltage source, the power-good signal generator comprising:
an impedance element of which an end is coupled to a second voltage source; a controlled transistor having a first input/output end coupled to the other end of the impedance element to generate the power-good signal, a second input/output end coupled a common potential and a controlled end coupled to the controller, wherein an operating state of the controlled transistor is changed in response to the control signal of the controller; and a power sequencing free circuit coupled to the controlled end of the controlled transistor and one of the first input/output end of the controlled transistor and the second voltage source; wherein when the second voltage source is provided before the first voltage source is provided, the power sequencing free circuit turns on the controlled transistor to clamp a voltage level of the power-good signal to be lower than a predetermined voltage level.