CMOS temperature sensor with sensitivity set by current-mirror and resistor ratios without limiting DC bias

摘要

An on-chip temperature sensor circuit can be implemented in a standard complementary metal-oxide-semiconductor (CMOS) process using PNP transistors. A pair of transistors have collector currents that are sensitive to voltage, both directly and due to saturation currents. A scaling resistor connects to the emitter of one transistor and its voltage compared to the other transistor's emitter voltage by an error amplifier that generates a bias voltage to current sources that are proportional to absolute temperature since the saturation current sensitivity is subtracted out. The current is mirrored to sink current through a multiplier resistor from an output. An amplifier connected across the multiplier resistor compares a reference voltage to set the DC bias independent of temperature sensitivity. The temperature sensitivity is proportional to the ratio of the multiplier resistor and the scaling resistor, and is multiplied by a mirroring factor. A differential output may also be provided.

主权项

1. A temperature sensor circuit comprising:
a first junction that produces a first voltage on a first node that is sensitive to temperature; a scaling resistor coupled between the first node and a first sense node; a first current source for sourcing a first current to the first sense node in response to a bias voltage; a second junction that produces a second voltage on a second node that is sensitive to temperature; a second current source for sourcing a second current to the second node in response to the bias voltage; an error amplifier that compares the first sense node to the second node to generate the bias voltage; a third current source for sourcing a third current in response to the bias voltage; a first current sink that sinks the third current to generate a second bias voltage that adjusts the first current sink to sink the third current; a second current sink that receives the second bias voltage and generates a sink current that is sunk from a multiplier node; a multiplier resistor coupled between multiplier node and an output; and an amplifier having the multiplier node as a first input and a receiving a reference voltage as a second input, the amplifier driving the output in response to a voltage difference between the reference voltage and a voltage on the multiplier node.