Abstract: A power supply switching circuit arrangement is configured to provide a relatively smooth (low noise) power supply switch-over during the transition between active and quiescent modes. Complementary inputs of an operational amplifier are selective coupled to feedback paths to the amplifier and the power supply switching circuit arrangement, so as to bias a switching transistor during system active mode at a value that is just slightly below the turn-on voltage of the transistor. This means that turning on the switching transistor for the purpose of providing quiescent mode powering of the utility device requires only a small transition in control voltage from an active mode ‘almost turned-on’ level.

Abstract: A tracking soft start circuit architecture contains a plurality of soft start circuits for generating a plurality of soft start voltages during startup for application to associated power supply terminals of a power supply system. The soft start circuits are interconnected in such a manner that prevents any soft start circuit from generating a soft start voltage waveform until all of the controlled power output devices have been brought to the same prescribed state of operation, that is, all power FET gates are precharged and their source voltages match each other.

Abstract: A power supply switching circuit arrangement is configured to provide a relatively smooth (low noise) power supply switch-over during the transition between active and quiescent modes. Complementary inputs of an operational amplifier are selective coupled to feedback paths to the amplifier and the power supply switching circuit arrangement, so as to bias a switching transistor during system active mode at a value that is just slightly below the turn-on voltage of the transistor. This means that turning on the switching transistor for the purpose of providing quiescent mode powering of the utility device requires only a small transition in control voltage from an active mode ‘almost turned-on’ level.

Abstract: A transconductance amplifier suitable for the input stage of a comparator with the capability of amplifying input signals with common mode voltage components in a range including the entirety of its operating voltage. Operation at one voltage extreme is accomplished by use of a long tailed pair connection of a pair of bulk modulated FETs with gates at the input terminals of the amplifier. Operation at the other voltage extreme is accomplished by the use of a pair of FETs in a source follower mode to drive common gate transistors of opposite polarity, the gates of the FETs also being connected to the input terminals of the amplifier. A common high impedance load for the comparator is connected to current mirrors of the drains of both pairs of FETs in the amplifier. The circuit may be implemented with bipolar transistors and additional amplification provided. Methods of comparing voltages are also disclosed.

Abstract: An automatic fault monitoring system prevents the detection of fault conditions during operating modes or conditions that can produce false fault conditions. A motor control system that utilizes an H-bridge circuit having active devices, preferably field effect transistors, in each arm of the bridge. The motor is connected in the leg of the bridge. Currents and voltages are sensed in each arm as different operating conditions represented by input control signals, which may be computer generated, drive the bridge and place the transistors in different states (on or off). Such operating conditions include rotation of the motor in opposite directions and reversal of direction. Fault detection logic is responsive to currents and voltages in the arms and leg of the bridge and provides outputs indicative of over-current fault conditions in the arm and open circuit fault conditions in the leg.