Abstract: A compact polarity-insensitive integrated circuit amplifier is described designed to be powered by a miniature low voltage battery of variable polarity. Low current, polarity corrected voltage sources are integrated into functional blocks to supply low current non-bidirectional elements and to provide a constant polarity bias to a substrate of CMOS circuits. Polarity corrected voltage sources are used to provide a polarity sensing function. The invention is embodied in a Class D amplifier which may comprise four n-channel MOSFET transistors arranged in an H-bridge configuration. Additional driver circuitry is described which increases the voltage of the pulse-width modulated input signal to the MOSFET transistors and also performs a pulse trimming function, which reduces parasitic crowbar currents in the amplifier output stage.

Abstract: A compact polarity-insensitive integrated circuit amplifier is described designed to be powered by a miniature low voltage battery of variable polarity. Low current, polarity corrected voltage sources are integrated into functional blocks to supply low current non-bidirectional elements and to provide a constant polarity bias to a substrate of CMOS circuits. Polarity corrected voltage sources are used to provide a polarity sensing function. The invention is embodied in a Class D amplifier which may comprise four n-channel MOSFET transistors arranged in an H-bridge configuration. Additional driver circuitry is described which increases the voltage of the pulse-width modulated input signal to the MOSFET transistors and also performs a pulse trimming function, which reduces parasitic crowbar currents in the amplifier output stage.

Abstract: A rectifier circuit produces an output which is a function of the magnitude of an input signal and has a controllable transient response. The circuit requires no rectification diodes. The voltage on a capacitor is sensed and compared with that of an input voltage. The operation of charging and discharging switches is adjusted by a control circuit to charge the capacitor if the magnitude of the input signal is greater than the capacitor voltage and to discharge the capacitor if the magnitude of the input signal is less than the capacitor voltage. The attack and release function of the rectifier is selectable by limiting the rate at which current charges/discharges the capacitor, preferably with constant current sources comprised of current mirrors. Multiple time constants are achieved by replicating the storage capacitor and charge/discharge elements configured with different time constants and then summing the resultant capacitor voltages.

Abstract: An integrated transient voltage pulse multiplier is used to increase the voltage to the gates of control switches in a low voltage circuit. The increased conductance of the control switches permits a reduction in gate width, reducing parasitic charge injection and capacitive feedthrough. A low distortion switched capacitor filter utilizes two transient voltage pulse multipliers to increase the voltage of non-overlapping clock signals. The switched capacitor filter is operative at a power supply voltage of less than 1.5 volts.

Abstract: An audio compressor utilizes a switched charging state rectifier which produces an output proportional to the magnitude of an input signal but with controlled attack/release times. The rectified voltage is input to a logical selector, which provides logical control signals which are a function of the rectified voltage. In a preferred embodiment, the control signals of the logical selector are used to select the switch positions of a switched resistor ladder. The switched resistor ladder is used to provide a resistance path in an op-amp feedback amplifier, thereby enabling the gain of the op-amp amplifier to be adjusted in steps by the selector as the rectified signal level varies.

Abstract: A digital to analog converter has a decoder configured to select weighted decoding elements in a decoding network. The decoded outputs increase in steps by a mathematical progression as a function of the value of the input to the decoder. A calibration circuit adjusts the value of the digital input code received by the decoder to achieve a calibration function. In a programmable resistor embodiment, the value of the resistance selected by subsequent digital codes increases by a constant ratio. An adder is used to add an offset value to the digital input, thereby shifting the value of the resistance selected by the decoder to compensate for fabrication variances.

Abstract: A battery polarity insensitive amplifier utilizes a power management architecture to reduce the size of the circuitry used to accomplish the polarity correction function. An efficient Class D amplifier and compact voltage multiplying driver circuit reduce the size of the battery polarity insensitive amplifier circuit.