for inductive loadsBidirectional pulse width modulationThe A4973 (PWM) current control design is capable of continuously delivering up to ±1.5 amps and operating at 50 volts. Internal fixed downtime pulse width modulation (PWM) current control circuitry can be used to regulate the maximum load current to the desired value. The peak load current limit can be set by the user by selecting the input reference voltage and an external sense resistor. The user can set the fixed downtime pulse duration by selecting an external RC timing network. Internal circuit protection includes thermal shutdown with delay,Transient suppression diodesand cross-current protection. No special power-on sequencing is required.
While the Enable input is kept low, the Phase input controls the polarity of the load current by selecting the appropriate source to pair with the sink driver. The "mode" input determines whether the pulse-width modulation (PWM) current control circuit operates in slow current attenuation mode (referring only to the selected source driver switch) or in faster current attenuation mode (selected source and sink switches). A user-selectable blank window prevents false triggering of the PWM current control circuitry. While the Enable input remains high, all output drives are disabled. Sleep mode reduces power consumption.
When logic low is applied in the Brake input, the brake function is enabled. As a result, the "on" and "phase" of the two source drivers become "off" and the two sink drivers become "on". This braking function can be used to dynamically brake brushed DC motors.
The A4973 is available in two power packages: a 16-pin dual in-line plastic package with copper heatsink and a 16-pin plastic SOIC with copper heatsink. For both packages, the power interface is at ground potential and does not require electrical isolation. Each package is Pb-free and features 100% matte tin leadframe plating.
- ±1.5 amps continuous output current
- 50 volt output voltage rating
- 3 volts to 5.5 volts logic supply voltage
- Internal PWM current control
- Fast and slow current decay mode
- Sleep (low current consumption) mode
- Internal transient suppression diode
- Internal thermal shutdown circuitry
- Crossover current and UVLO protection