SBASAJ9B June 2022 – December 2024 AMC22C12-Q1
PRODUCTION DATA
Isolated amplifiers such as the AMC1211-Q1 are widely used for measuring the DC link voltage in onboard chargers (OBC), DC/DC converters, and traction inverters. Power stages connected to the DC link rail can be sensitive to overvoltage conditions that can occur (for example, during a braking operation). The isolated amplifier is not always able to alert the system controller fast enough to take appropriate action to reduce the DC link voltage. Therefore, a fast, isolated comparator is required to detect overvoltage conditions.
Figure 7-2 shows a simplified schematic of a traction inverter where the DC link voltage is sensed by an AMC1211-Q1 isolated amplifier. The AMC22C12-Q1 is connected parallel to the AMC1211-Q1 and monitors the voltage across RSNS for overvoltage conditions. The overvoltage trip-threshold is set by the R1 resistor connected to the REF pin of the AMC22C12-Q1. The open-drain OUT pin of the AMC22C12-Q1 is connected to a GPIO or interrupt pin of the MCU and is actively pulled low whenever the input voltage (VIN) exceeds the reference voltage (VREF).