Squelch detector
AssigneeGigadevice Semiconductor Inc.
InventorsDequan Hou, Sanlin Liu
Life of this patent
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Abstract
A squelch detector is disclosed by the present application. By configuring the first to third bias current sources and a mirror ratio of the current mirror circuit, when an amplitude difference between first and second input signals is smaller or greater than a squelch threshold, flip of an output node in the squelch detector depends only on the squelch threshold and is independent of variations of process, voltage and temperature (PVT) parameters. Thus, the squelch detector can always provide reliable amplitude detection of input signals despite of possible variations of the PVT parameters.
Claims18
A squelch detector comprising an amplitude comparator circuit, wherein the amplitude comparator circuit comprises:
- a squelch threshold setting circuit coupled to each of a first bias current source, a first reference voltage and a second reference voltage, wherein the squelch threshold setting circuit is configured to set a squelch threshold of the squelch detector to be equal to a difference between the first reference voltage and the second reference voltage, and to generate a current associated with the first bias current source and the squelch threshold;
- a signal input circuit coupled to each of a second bias current source, a first input signal and a second input signal, wherein the signal input circuit is configured to generate, based on the second bias current source, a current associated with an amplitude difference between the first input signal and the second input signal;
- and
- a current mirror circuit coupled to each of a third bias current source, the squelch threshold setting circuit and the signal input circuit, wherein the current mirror circuit is configured to:
- generate a first mirror current of the current output from the squelch threshold setting circuit, generate a difference current between the current output from the signal input circuit and the first mirror current, and generate a second mirror current of the difference current;
- and provide the third bias current source and the second mirror current to a corresponding output node in the squelch detector to control a flip of the output node,
- wherein when the second mirror current is greater or smaller than the third bias current source, the output node is flipped.
Dependencies are inferred from the claim text.