HV9901

The Supertex 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 8 to 450V DC through utilization of the relay coils' inductance.

The circuit HV9901 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 5V coil relays for DC voltages 8 - 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 1mA capability that can be used to supply low power microcontrollers.

The pull-in current, pull-in time and hold current are all programmable 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.