Load driving circuit, display driver, display device and semiconductor device

The load driving circuit with a push-pull output stage and mirror current detection enhances sensitivity and precision in detecting abnormalities in display devices, addressing the challenges of high sensitivity, precision, and speed while preventing device size increase.

JP7750722B2Active Publication Date: 2025-10-07ROHM CO LTD
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Patent Information

Application Number
JP2021194370
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Filing Date
2021-11-30
Publication Date
2025-10-07
Estimated Expiration
2041-11-30

AI Technical Summary

Technical Problem

Existing display devices face challenges in detecting abnormalities in the current output to the load with high sensitivity, precision, and speed, while also facing increased chip size and costs due to the use of circuits operating at higher power supply voltages.

Method used

A load driving circuit with a push-pull output stage composed of first and second output stage transistors of different conductivity types, an output amplifier, and a detection circuit that generates mirror currents to detect deviations in the output current using a coupling circuit, which sets current ratios to enhance sensitivity and precision without increasing device size.

Benefits of technology

The solution allows for quick, accurate, and sensitive detection of abnormalities in the current output to the load without increasing device size, using a simple configuration that does not rely on resistive elements or comparators.

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Abstract

PURPOSE: To provide a load drive circuit, a display driver, a display device, and a semiconductor device with which it is possible to detect the abnormality of an output current with high sensitivity and high accuracy, and at high speed.CONSTITUTION: The present invention comprises an output amplifier having a push-pull output stage composed of a first and a second output stage transistor, and a detection circuit for detecting the abnormality of the output current that is outputted by the output amplifier. The detection circuit includes: a coupling circuit for generating each of a first and a second current having been mirrored from the current flowing in the first output stage transistor and each of a third and a fourth current having been mirrored from the current flowing in the second output stage transistor, and coupling the first and third currents at a first output node and outputting the voltage of the first output node as a first voltage, as well as coupling the second and fourth currents at a second output node and outputting the voltage of the second output node as a second voltage; and a determination circuit for outputting a determination signal that represents abnormality or normalcy on the basis of the first and second voltages. The coupling circuit generates the first to fourth currents so that the third current is larger than the first current, and the second current is larger than the fourth current at reference state time.SELECTED DRAWING: Figure 2A
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Citation Information

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