US 11,233,590 B2 · Voltage detector and communication circuit including voltage detector

Abstract

Disclosed is a voltage detector and a communication circuit capable of detecting a low input voltage. The voltage detector includes: an alternating-current coupling circuit generating a first and a second input voltages according to a source input voltage; a feedback amplifier outputting a branch current according to a sink current including the branch current, and determining an output voltage according to the first input voltage and the amount of the branch current; and an auxiliary circuit outputting the amount of the sink current according to the second input voltage. When the sink current increases as the second input voltage rises, the branch current also increases, so that the output voltage not only rises as the first input voltage rises but also rises as the branch current increases. This feature allows a lower input voltage to be detectable by the detection of the risen output voltage.

Claims16

Dependent claims

A voltage detector comprising:

an alternating-current coupling circuit configured to generate a first input voltage and a second input voltage according to a source input voltage;
a feedback amplifier configured to output a branch current according to a sink current and determine an output voltage according to the first input voltage and an amount of the branch current;
and
an auxiliary circuit configured to output an amount of the sink current according to the second input voltage, wherein the sink current includes a sum of a predetermined current from a current source of the auxiliary circuit and the branch current, and the branch current is not outputted from the current source.

1 more element

A voltage detector comprising:

an alternating-current coupling circuit configured to generate a first input voltage and a second input voltage according to a source input voltage;
a feedback amplifier configured to output a branch current according to a sink current and determine an output voltage according to the first input voltage and an amount of the branch current;
and
an auxiliary circuit configured to output an amount of the sink current according to the second input voltage, wherein the sink current includes the branch current,
wherein the source input voltage is composed of two voltages of a differential signal, the first input voltage is composed of two voltages of another differential signal, and the second input voltage is composed of two voltages of yet another differential signal, and the alternating-current coupling circuit includes:
a first terminal configured to receive a positive-terminal input of the source input voltage;
a second terminal configured to receive a negative-terminal input of the source input voltage;
a first alternating-current coupling circuit configured to generate the first input voltage according to the positive-terminal input, the negative-terminal input and a first bias;
and
a second alternating-current coupling circuit configured to generate the second input voltage according to the positive-terminal input, the negative-terminal input and a second bias.

7 more elements

A communication circuit including a voltage detector, the communication circuit comprising:

a radio-frequency circuit configured to process a reception signal according to an amplifier gain and thereby generate a source input voltage;
the voltage detector including:
an alternating-current coupling circuit configured to generate a first input voltage and a second input voltage according to the source input voltage;
a feedback amplifier configured to output a branch current according to a sink current and determine an output voltage according to the first input voltage and an amount of the branch current;
and
an auxiliary circuit configured to output an amount of the sink current according to the second input voltage, wherein the sink current includes a sum of a predetermined current from a current source of the auxiliary circuit and the branch current, and the branch current is not outputted from the current source;
a comparing circuit configured to compare the output voltage with a threshold voltage and thereby generate a voltage detection result;
and
a gain adjusting circuit configured to adjust the amplifier gain according to the voltage detection result.

6 more elements

Dependencies are inferred from the claim text.

Voltage detector and communication circuit including voltage detector

Life of this patent

Voltage detector and communication circuit including voltage detector

Life of this patent

Abstract

Claims16