HV9901 is a BiCMOS/DMOS universal relay driver that employs PWM switching techniques. It is designed for efficient and energy-saving operation of a low voltage relay with supply voltages ranging from 10 to 450V DC through utilization of the relay coils’ inductance.The circuit is capable of operating over a wide input voltage range without requiring a change of any external components. For example, this will enable users to use 5.0V coil relays for DC voltages 10 to 450V or AC voltages up to 240V.The HV9901 has an internal high-voltage regulator to power internal PWM circuitry. Additionally, it includes an adjustable auxiliary regulator with a 1.0mA capability that can be used to supply low power micro controllers.The pull-in current, pull-in time and hold current are all program-mable using only two resistors and a capacitor. The PWM switching frequency can be either:- Synchronized to an external clock, or- Synchronized to other HV9901s, where the synchronized frequency is the highest free-running frequency.The enable (ENI) logic input is used to turn the relay on/off. Enable polarity may be selected via the POL input. Audible noise is prevented using fixed switching frequencies above 20kHz.WARNING!!! Galvanic isolation is not provided. Dangerous voltages are present when connected to the AC line. It is the responsibility of the designer to ensure adequate safeguards are in place to protect the end user from electrical shock.

  10 to 450V input voltage range

  Energy saving hold current mode

   Adjustable microcontroller supply

  Low supply current <1.0mA

  Constant current coil

  Programmable pull-in current, pull-in time, and hold current

  Efficient PWM operation using the relay coils’ inductance