Light sensor circuit and photocurrent detection method thereof
By setting a first capacitor between the photodiode and the operational amplifier and utilizing the virtual short characteristic of the operational amplifier, the bias voltage of the photodiode is kept at 0, thereby solving the influence of dark current on photocurrent measurement under weak light conditions and improving the sensitivity of the light sensor circuit.
CN115962847BActive Publication Date: 2025-09-09WUHAN JUXIN MICROELECTRONICS CO LTD
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Patent Information
- Application Number
- CN202111187670.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-10-12
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2041-10-12
AI Technical Summary
Technical Problem
When a photodiode measures light intensity under low-light conditions, the dark current has a significant impact on the photocurrent, resulting in inaccurate measurements and reducing the sensitivity of the light sensor circuit.
Method used
By setting a first capacitor between the photodiode and the operational amplifier and utilizing the virtual short characteristic of the operational amplifier, the bias voltage of the photodiode is kept at 0, thereby reducing dark current and improving the sensitivity of the light sensor circuit.
Benefits of technology
Under weak light conditions, the dark current of the photodiode is effectively reduced, the photocurrent measurement capability of the light sensor circuit is improved, and the sensitivity is enhanced.
✦ Generated by Eureka AI based on patent content.
Abstract
The present invention provides a light sensor circuit and a photocurrent detection method thereof. A first capacitor is provided to isolate a photodiode and an operational amplifier. The operational amplifier is used to maintain the potential at one end of the first capacitor constant and eliminate a current path through the first capacitor, thereby maintaining the charge stored in the first capacitor constant and the potential at the other end of the first capacitor constant. Furthermore, under the premise that the potential at the second end of the first capacitor is initially grounded to zero by a first switch, the potential at the second end of the first capacitor can be maintained at zero, thereby maintaining the bias potential of the photodiode at all times. Consequently, during the integration circuit formed by the second capacitor and the operational amplifier, the bias voltage of the photodiode can remain at all times zero, thereby significantly reducing the dark current of the photodiode and improving the circuit's ability to measure the photocurrent of the photodiode in low light conditions, thereby increasing the circuit's sensitivity.
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