Comparator, oscillator using the same, dc/dc converter, control circuit thereof, and electronic apparatus

摘要

A comparator compares a first input voltage and a second input voltage to generate a comparative output depending on a result of the comparison. The comparator includes a first input terminal configured to receive the first input voltage, a second input terminal configured to receive the second input voltage, a differential pair including a first input transistor whose control terminal is connected with the first input terminal and a second input transistor whose control terminal is connected with the second input terminal, a tail current source configured to supply a tail current to the differential pair, and a load circuit connected to the first input transistor and the second input transistor, and the tail current source increases the tail current, as the first input voltage approaches the second input voltage, depending on the first input voltage.

主权项

1. A comparator comparing a first input voltage and a second input voltage to generate a comparative output depending on a result of the comparison, comprising:
a first input terminal configured to receive the first input voltage; a second input terminal configured to receive the second input voltage; a differential pair including a first input transistor whose control terminal is connected with the first input terminal and a second input transistor whose control terminal is connected with the second input terminal; a tail current source configured to supply a tail current to the differential pair; and a load circuit connected to the first input transistor and the second input transistor, wherein the tail current source increases the tail current, as the first input voltage approaches the second input voltage, depending on the first input voltage, and wherein the tail current source includes: a first resistor provided between a first node and a fixed-voltage terminal, the first node being a common connection point of the first input transistor and the second input transistor; and a first variable current source configured to generate a current which increases as the first input voltage approaches the second input voltage depending on the first input voltage, the first variable current source being provided in parallel with the first resistor.