SLYY234 December 2024 AMC0106M05 , AMC0106M25 , AMC0136 , AMC0311D , AMC0311S , AMC0386 , AMC0386-Q1 , AMC1100 , AMC1106M05 , AMC1200 , AMC1200-Q1 , AMC1202 , AMC1203 , AMC1204 , AMC1211-Q1 , AMC1300 , AMC1300B-Q1 , AMC1301 , AMC1301-Q1 , AMC1302-Q1 , AMC1303M2510 , AMC1304L25 , AMC1304M25 , AMC1305M25 , AMC1305M25-Q1 , AMC1306M05 , AMC1306M25 , AMC1311 , AMC1311-Q1 , AMC131M03 , AMC1336 , AMC1336-Q1 , AMC1350 , AMC1350-Q1 , AMC23C12 , AMC3301 , AMC3330 , AMC3330-Q1
Isolated amplifiers can measure voltage or current with relatively high accuracy while keeping the measurements isolated from the low-side. This is useful in applications where the high-side voltage requires isolation for safety-related concerns, or when the high-side can experience sudden transients which can damage a controller on the low-side. Common applications include measuring a high-voltage motor bus or measuring motor phase current.
However, isolated amplifiers require the high-side power supply to be isolated from the low-side power supply, which can lead to increased size and complexity. One alternative is a transformer-isolated power supply, which produces the high-side rail from the low-side while keeping the high-side isolated from the low-side. However, transformers can be large and costly. A bootstrap charge-pump power supply is a cost-effective alternative. The power is supplied from a pulse-width modulation (PWM) signal, and only requires a capacitor, a diode, and a current-limiting resistor. In some cases, a linear dropout regulator (LDO) can be required as well.