Texas Instruments Corporation

David R Spady

Vadim Valerievich Ivanov

Stephen James Sanchez

David M Jones

A class AB output circuit includes a P-channel pullup transistor (M) having a source coupled to a supply voltage, a drain coupled to an output(), a gate coupled to respond to an input signal on an input(), an N-channel pulldown transistor (M) having a drain coupled to the output, a source coupled to ground, and a gate coupled to respond to the input signal. A first N-channel transistor (M) has a drain coupled to a gate of the output transistor and the supply voltage by means of a current source () and a source coupled to ground by means of a second current source (). A first diode-connected N-channel transistor (M), a second diode-connected N-channel transistor (M), and a first level shifting circuit () are coupled in series between ground and a gate of the N-channel transistor, and a current source () is coupled between the first supply voltage and the gate of the first N-channel transistor. A second level shifting circuit () is coupled between the gate of the pulldown transistor and the source of the first N-channel transistor.

Zero voltage class AB minimal delay output stage and method

A method and circuit is provided for improving the control of the trimming procedure for various devices without the need for additional dedicated control pins. Instead, the trimming procedure is controlled through sensing of changes in current and/or voltage applied through the existing available pins or bondpads of the devices to determine whether a command for trim programming has occurred. As a result, package-level trimming of the devices can be conducted in standard device packages having low pin count configurations, such as operational amplifiers, instrumentation amplifiers, difference amplifiers, low drop-out regulators, voltage references and other similar types of devices. A device to be trimmed is configured with internal circuitry configured to sense changes in current and/or voltage in the output or supply voltage of the device, and a test system for applying changes in the current and/or voltage through the existing available pins or bondpads of the devices. The internal circuitry can comprise sensing circuitry comprising one or more internal sensors configured to measure current and/or voltage in the output or supply voltage of the device, and can comprise trim programming circuitry for facilitating trim programming of the device.

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David R Spady