Temperature-compensated voltage comparator

A power supply, comprising:

• a switching regulator, the switching regulator including a current sense resistor;
• a temperature-compensated voltage comparator, coupled to the current sense resistor, for comparing a voltage across the current sense resistor, the temperature-compensated voltage comparator, further comprising:
• a first input terminal and a second input terminal for receiving, for comparison, a first input voltage and a second input voltage, respectively,
• a first bipolar junction transistor and a second bipolar junction transistor for converting the first input voltage and the second input voltage to a first input current and a second input current, respectively, wherein the first input current and the second input current are dependent upon temperature,
• a temperature-compensating circuit for generating a logarithmic temperature-compensating factor, wherein the logarithmic temperature-compensating factor compensates, at least in part, for temperature dependency of the first input current and the second input current, the temperature-compensating circuit including:
• an input for receiving the second input current, and
• an output for outputting a temperature-compensated current, wherein the temperature-compensated current is the second input current multiplied by the logarithmic temperature-compensating factor;
• a digital output voltage derived from the temperature-compensated current and the first input current, wherein the digital output voltage is indicative of a polarity of a differential between the first input voltage and the second input voltage;
• and
• a control module, coupled to the switching regulator and to the temperature-compensated voltage comparator, for using the digital output voltage to control operation of the power supply.

A temperature-compensated voltage comparator, comprising:

• a first input terminal and a second input terminal for receiving, for comparison, a first input voltage and a second input voltage, respectively;
• a first bipolar junction transistor and a second bipolar junction transistor for converting the first input voltage and the second input voltage to a first input current and a second input current, respectively, wherein the first input current and the second input current are dependent upon temperature;
• a first current mirror, coupled to the first bipolar junction transistor, for producing a mirror of the first input current;
• a second current mirror, coupled to the second bipolar junction transistor, for producing a mirror of the second input current;
• a third current mirror, coupled to the second current mirror, for producing, from the mirror of the second input current, another appearance of the second input current;
• a temperature-compensating circuit for generating a logarithmic temperature-compensating factor, wherein the logarithmic temperature-compensating factor compensates, at least in part, for temperature dependency of the first input current and the second input current, the temperature-compensating circuit including:
• an input for receiving, from the third current mirror, the second input current, and
• an output for outputting a temperature-compensated current, wherein the temperature-compensated current is the second input current multiplied by the logarithmic temperature-compensating factor;
• a fourth current mirror, coupled to the output of the temperature-compensating circuit, for producing, from the temperature-compensated current, a mirror of the temperature-compensated current;
• and
• a basic output node, coupled to the fourth current mirror and to the first current mirror, for summing the temperature-compensated current and the first input current, wherein a basic output voltage at the basic output node is indicative of a differential between the first input voltage and the second input voltage.