Electric vehicle service equipment (EVSE) facilitates power delivery to electric vehicles safely from the grid. An EVSE control system consists of an auxiliary power stage, an off-board AC/DC high power stage (only in DC charging stations), energy metering unit, AC and DC residual current detector, an isolation monitor unit, relays and contactors with drive, two-way communication over single wire, and service and user interfaces. This reference design highlights an ultra-low standby isolated AC/DC auxiliary power stage followed by converters and linear regulators, a comparator-based control pilot interface to meet the IEC61851 standard, an efficient relay and contactor drive, plug lock motor driver, flux gate circuit to detect AC and DC currents for RCD applications, and isolated line voltage sensing across the relay and contactor.
- Ultra-low standby UCC28742-based isolated 29-W AC/DC stage to improve energy efficiency
- Supercapacitor backup supplying up to 7.5 W for three seconds during energy storage release (AC mains failing)
- DRV8220 current controller to drive high-current relays and contactors for thermal protection, RCD AC and DC detection, and plug lock control
- Isolated line voltage sensing using the ISO1212 digital-input receiver for welded relay and contactor detection
- Tight output voltage regulation (< ±5%) of LDOs and the high slew rate of the TLV1805 device for control pilot interface