MA838

The MA838 PWM generator has been designed to provide waveforms for the control of variable speed AC machines, uninterruptible power supplies and other forms of power electronic devices which require pulse width modulation as a means of efficient power control.

Two TTL level PWM outputs control the upper and lower switches in an inverter arm. This is usually via an external isolation and amplification stage.

Information contained within the pulse width modulated sequences controls the wave shape, power frequency and amplitude of the output waveform. Parameters such as the carrier frequency, minimum pulse width and pulse delay time may be defined during initialisation of the device. The pulse delay time (underlap) controls the delay between turning on and off the two power switches in the inverter, in order to accommodate variations in the turn-on and turn-off times of families of power devices.

The MA838 is easily controlled by a microprocessor and its fully digital generation of PWM waveforms gives unprecedented accuracy and temperature stability. Precision pulse shaping capability allows optimum efficiency with any power circuitry. The device operates as a stand-alone microprocessor peripheral reading the power waveform directly from an internal ROM and requiring microprocessor intervention only when operating parameters need to be changed.

An 8-bit multiplexed data bus is used to receive addresses and data from the microprocessor/controller. This is a standard MOTEL™ bus, compatible with most microprocessors/ controllers.