Zetex Semiconductors (UK), a subsidiary of Zetex plc (Chadderton, Oldham), announced its ZXBM1015 pre-driver IC for variable or fixed-speed control of single-phase, brushless dc fans, blowers and pumps. The ZXBM1015 includes a current monitor that enables supply current on startup and stall to be kept permanently within OEM specifications.
The ZXBM1015 produces a PWM output to drive an external H-bridge that drives the motor windings. Its integral current-monitoring circuit measures the voltage across a low-value external resistor in the low side of the H-bridge, and deduces how much current the motor is taking during each PWM cycle. If it takes too much, the pre-driver backs off the PWM drive to reduce the current drawn.
The pre-driver IC offers a configurable phase commutation delay. The ZXBM1015 has a fixed internal commutation delay of 100 µs, which can be extended or reduced by the addition of an external resistor. The ZXBM1015 solution is compatible with thermistor, voltage and PWM control inputs, which support fully adjustable motor speed control in a wide range of equipment – from desktop computers to central heating systems.
With a built-in Hall amplifier, the pre-driver is compatible with any type of Hall-effect sensor, and can provide pulsed rotor speed and locked rotor alarm outputs. For a locked rotor condition, the ZXBM1015 puts motor drive outputs into a safe operating mode to protect the H-bridge and motor windings.
The ZXBM1015 is priced at $0.88 in 1,000-piece quantities.