Isolated switch controller monitors up to 1kV DC

Article By : Linear Technology

A 5kVRMS galvanic isolation barrier inside the LTM9100 protects up to 1kV DC, with the I2C/SMBus interface for power and energy monitoring.

Linear Technology has introduced the LTM9100 µModule, an all-in-one isolated anyside switch controller that protects and monitors high voltage DC power supplies up to 1kV.

High voltage supplies used in industrial, datacom, avionic and medical applications require a controlled turn-on, with isolation needed for control circuit protection, operator safety and breaking ground paths, but alternative relay-based or discrete solutions are bulky, complex, component-intensive and lack safety certifications.

Linear said the LTM9100 saves design time, certification effort and board area by wrapping all the needed functionality, including isolated power and digital telemetry, in a compact BGA package.

 

Figure 1: Linear Technology’s 5kVRMS isolated switch controller.
 

A 5kVRMS galvanic isolation barrier inside the LTM9100 separates the digital interface from the switch controller, driving an external N-channel MOSFET or IGBT switch. TThe controller is production-tested to 6kVRMS and will be recognised by the component-level UL 1577 standard, saving months of certification time for the end equipment manufacturer, according to the company. Isolated digital measurements of load current, bus voltage and temperature are accessed via the I2C/SMBus interface, enabling power and energy monitoring of the high-voltage bus.

 

Figure 2: A 5kVRMS galvanic isolation barrier inside the LTM9100 separates the digital interface from the switch controller, driving an external N-channel MOSFET or IGBT switch.
 

Due to its isolated nature, the LTM9100 is easily configured for high side, low side (ground return) and floating applications. In-rush current is minimised by soft-starting the load, and the supply is protected from overload and short-circuits with a current-limited circuit breaker. The LTM9100 can control in-rush current in hot-swappable cards, AC transformers, motor drives and inductive loads. Adjustable undervoltage and overvoltage lockout thresholds ensure that the load operates only when the input supply is in its valid range. A fully integrated DC/DC converter, including the transformer, powers the isolated switch control side.

 

Figure 3: In-rush current is minimised by soft-starting the load, and the supply is protected from overload and short-circuits with a current-limited circuit breaker.
 

Specified over the −40°C to 105°C temperature range, the LTM9100 comes in a 22mm x 9mm x 5.16mm BGA package, with 14.6mm of creepage distance between the logic side and the isolated side. 1,000-piece pricing starts at $19.45 each.