Abstract: A miniaturized switching power supply has an output circuit for supplying gate drive to a power FET. The output circuit incorporates a pair of series connected transistors with a zener diode connected to the base of one of the transistors to limit the gate drive to the FET.

Abstract: A high frequency miniaturized switching power supply has a unidirectional spike filter which removes spikes appearing on a feedback signal before such feedback signal is provided to the comparator of the switching power supply. The spike filter removes voltage spikes of one polarity without lengthening the reset time of the comparator in response to a wavefront of the opposite polarity.

Abstract: An improved design for an optical encoder with a compensation feedback signal for compensating for effects of time and temperature on the photoemission characteristics of the encoder's light source. By using a current mirror, the photodiodes which normally provide only the data signal now provide both the data signal and the compensation feedback signal, thereby eliminating the need for a separate, dedicated photodiode for the compensation feedback signal. This results in eliminating the necessity of matching the electrical operating characteristics of the data photodiodes to those of a compensation feedback photodiode. This further results in eliminating the large die area required for including a compensation feedback photodiode in an integrated circuit design.

Abstract: A transducer in the form of an integrated circuit comprising a Hall cell, first and second differential amplifiers, an output driver stage, a threshold voltage-generating circuit between said amplifiers, and a control circuit for selectively enabling and disabling the threshold voltage-generating circuit. The second amplifier provides an output signal representative of the enabled-disabled condition of the threshold voltage-generating circuit. A permanent magnet having a temperature coefficient is movable with respect to the transducer between given field-applying and field-removing positions. The transducer operates to change switching states between "operate" and "release" in response to the two different levels of applied magnetic fields, respectively, resulting from the two given operating positions of the magnet.

Abstract: Hall-effect position sensor apparatus is disclosed which senses the position of a moving body and provides an output signal indicative of the position of the moving body. The apparatus includes a predetermined number of Hall-effect sensors which are positioned in a straight line and in operating proximity to a moving body made of a ferromagnetic material. A permanent magnet is operatively positioned such that the Hall-effect sensors lie in the magnetic field produced by the magnet while the moving body provides a portion of the path comprising the magnetic excitation circuit with the permanent magnet. The moving body includes portions devoid of ferromagnetic material, which causes a change in the magnetic field.

Abstract: Automatic brightness control apparatus for providing real time control of the brightness of various types of displays while also providing ambient light compensation is disclosed which includes a photodiode for providing a current proportional to the ambient light level. Amplifiers, together with a load, change the photodiode current to a control voltage indicating the level of ambient light. The control voltage is provided as a reference input to a voltage comparator. The other input to the voltage comparator is the output of a free running ramp oscillator. The pulse width modulated logic signal comprising the output of the voltage comparator is provided as the input for an output driver whose pulse stream output is used to control the brightness of the designated display. The duty cycle of the pulse stream output varies with the ambient light level.