Power on ready signal generating apparatus and operation method thereof

A power on ready (POR) signal generating apparatus, comprising:

• a detection circuit, configured to detect a target voltage, wherein the detection circuit sets a POR signal to a ready state when the target voltage is ready;
• and
• a control circuit, coupled to an output terminal of the detection circuit to receive the POR signal, wherein the control circuit maintains the POR signal in the ready state and disables the detection circuit after the POR signal transitions from a not ready state to the ready state, wherein the control circuit comprises:
• a trigger circuit, comprising an input terminal coupled to the output terminal of the detection circuit to receive the POR signal, wherein an output terminal of the trigger circuit outputs an enable signal related to the POR signal;
• and
• a first switch, comprising a first terminal configured to receive a power voltage, wherein a second terminal of the first switch is coupled to the output terminal of the detection circuit, and a control terminal of the first switch is coupled to the output terminal of the trigger circuit to receive the enable signal;
• wherein the enable signal turns on the first switch after the POR signal transitions from the not ready state to the ready state,
• wherein the trigger circuit comprises:
• a delay circuit, comprising an input terminal coupled to the output terminal of the detection circuit to receive the POR signal, wherein an output terminal of the delay circuit outputs a delayed signal;
• and
• a first buffer, comprising an input terminal coupled to the output terminal of the delay circuit to receive the delayed signal, wherein an output terminal of the buffer outputs the enable signal.

An operation method of a power on ready (POR) signal generating apparatus, comprising:

• detecting a target voltage by a detection circuit, comprising:
• receiving the target voltage to generate a delayed target voltage by a delay circuit of the detection circuit;
• and
• comparing the delayed target voltage with a first reference voltage to obtain a comparison result and setting a POR signal according to the comparison result by a voltage detection circuit of the detection circuit;
• setting, by the detection circuit, the POR signal to a ready state when the target voltage is ready;
• and
• maintaining the POR signal in the ready state and disabling the detection circuit by a control circuit after the POR signal transitions from a not ready state to the ready state.