SBAS945A February 2022 – July 2022 AMC23C14
PRODUCTION DATA
Fast overcurrent and short-circuit current detection is a common requirement in DC/DC converter and motor-control applications, and can be implemented with an AMC23C14 isolated window comparator as shown in Figure 8-1.
The load current flowing through an external shunt resistor RSHUNT produces a voltage drop that is sensed by the AMC1300B for control purposes. The same voltage is monitored by the AMC23C14 that is connected in parallel to the current-sensing amplifier and provides a fast sensing path for positive and negative fault-current detection. The trip threshold for overcurrent detection is set by the external resistor R1. The trip threshold for short-circuit detection is fixed by the internal 300-mV reference. Overcurrent conditions are signaled on OUT1, and short-circuit conditions are signaled on OUT2.
As depicted in Figure 8-1, the integrated low-dropout (LDO) regulator on the high-side allows direct connection of the VDD1 input to a commonly used floating gate-driver supply. Alternatively, the AMC23C14 can share a regulated supply with the AMC1300B. In that case, the VDD1 pin of the AMC23C14 connects directly to the VDD1 pin of the AMC1300B and R4 is not needed. The fast response time and high common-mode transient immunity (CMTI) of the AMC23C14 ensure reliable and accurate operation even in high-noise environments.