Abstract: A high voltage waveform is generated that is similar to a low voltage input waveform. The high voltage waveform is a series of pulses that are applied directly to the device. An error signal controls the frequency, magnitude, and duration of the pulses. A feedback signal derived from the high voltage waveform is compared with the input waveform to produce the error signal.

Abstract: A high voltage waveform is generated that is similar to a low voltage input waveform. The high voltage waveform is a series of pulses that are applied directly to the device. An error signal controls the frequency, magnitude, and duration of the pulses. A feedback signal derived from the high voltage waveform is compared with the input waveform to produce the error signal.

Abstract: A signal for controlling output voltage from the driver is modulated by the input signal to the driver, whereby the output voltage tracks the input signal, matching power to demand. The output storage capacitor can be reduced in size because the amount of energy that needs to be stored is reduced. In addition, feedback transistors are paired on the same substrate and cause opposite changes in response to changes in temperature, thereby automatically compensating for changes in temperature without the use of additional components.

Abstract: A driver for a piezoelectric actuator includes a pulse width modulator and an output amplifier packaged as a single semiconductor device, preferably on a single semiconductor die. The driver includes a first boost converter that supplies power to the output amplifier, which preferably has programmable gain. A second amplifier, for driving the gate of a switching transistor in the first boost converter, is powered by a second boost converter. The piezoelectric actuator provides tactile feedback for the keyboard or the display in a battery operated electronic device.

Abstract: A driver includes a boost converter, a pulse width modulator controlling the boost converter, and a timer controlling the pulse width modulator. The timer, such as a digital counter, causes the pulse width modulator to produce narrow pulses unless or until the end of a period is reached, at which point the pulse width modulator is not controlled by the timer.