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CN-117516703-B - Light sensor with voltage reversal mechanism

CN117516703BCN 117516703 BCN117516703 BCN 117516703BCN-117516703-B

Abstract

The invention discloses a light sensor with a voltage reversing mechanism. In the first phase time, the photoelectric component converts the first optical signal into a first photocurrent for charging the capacitor to a first voltage, and the counter counts a first rough estimation value according to the first photocurrent. The photoelectric component converts the second optical signal into a second photocurrent in a second phase time for charging the capacitor from the inverted first voltage to a second voltage, and the counter counts a second rough estimate value accordingly. After counting the second rough estimate count value, the counter counts the fine count value according to the second rough estimate count value. One of the first photoelectric signal and the second photoelectric signal is a light signal reflected by the object to be detected after being emitted by both the ambient light source and the light emitting component, and the other is a light signal emitted by the pure ambient light source.

Inventors

  • Hong jiahua
  • CHEN ZHIYUAN

Assignees

  • 茂达电子股份有限公司

Dates

Publication Date
20260512
Application Date
20220803
Priority Date
20220727

Claims (12)

  1. 1. A photosensor having a voltage reversal mechanism, the photosensor having a voltage reversal mechanism comprising: An optoelectronic component configured to convert optical energy of a received first optical signal into a first photocurrent to provide to a capacitor to charge a voltage of the capacitor to a first voltage; a voltage reversing circuit connected to the capacitor and configured to reverse the first voltage to form a reversed voltage; a comparator having a first input connected to the capacitor, a second input coupled to a reference voltage, the comparator configured to compare the first voltage with the reference voltage to output a first comparison signal, and The input end of the counter is connected with the output end of the comparator, and the counter is configured to count according to the first comparison signal so as to output a first rough estimation value; Wherein after counting to output the first rough estimate count value, the optoelectronic assembly converts optical energy of the received second optical signal into a second photocurrent to provide to the capacitor to charge a voltage of the capacitor from the reverse voltage to a second voltage; The comparator compares the second voltage with the reference voltage to output a second comparison signal, and the counter counts according to the second comparison signal to output a second rough estimation value; Wherein after counting to output the second rough estimate count value, the counter performs a fine count operation on the second rough estimate count value to calculate a fine count value; one of the first optical signal and the second optical signal is an optical signal reflected by the object to be detected after being emitted by both the ambient light source and the light emitting component, and the other of the first optical signal and the second optical signal is an optical signal emitted by only the ambient light source.
  2. 2. The photosensor with a voltage reversing mechanism according to claim 1, wherein the voltage reversing circuit reverses the first voltage that is positive to form the reversed voltage that is negative, the absolute value of the reversed voltage being equal to the first voltage.
  3. 3. The light sensor with voltage reversal mechanism according to claim 1, characterized in that the second photocurrent charges the voltage of the capacitor from the reversed voltage, which is negative, to the second voltage, which is positive.
  4. 4. The light sensor with voltage reversal mechanism of claim 1, wherein the light emitting assembly emits light signals simultaneously with the ambient light source for a first phase time when the energy of the light signals emitted by the ambient light source is above an energy threshold, the counter counting to output the first rough estimate count value; Wherein after the end of the first phase time, a second phase time is entered in which only the ambient light source emits a light signal, and the counter counts to output the second rough estimate value.
  5. 5. The light sensor with voltage reversal mechanism according to claim 1, characterized in that the ambient light source emits light signals only during a first phase time when the energy of the light signals emitted by the ambient light source is below an energy threshold, the counter counting to output the first rough estimate value; and after the first phase time is finished, entering a second phase time, wherein the light emitting component and the environment light source emit light signals simultaneously in the second phase time, and the counter counts to output the second rough estimation value.
  6. 6. The light sensor with voltage reversing mechanism of claim 1, further comprising a current supply component coupled to the capacitor and configured to provide a bias current to the capacitor to charge the capacitor while the second photocurrent is provided to the capacitor.
  7. 7. The light sensor with voltage reversal mechanism of claim 6, wherein the current supply component is configured to provide the bias current to the capacitor to charge the capacitor at the same time as the first photocurrent is provided to the capacitor.
  8. 8. The light sensor with voltage reversing mechanism of claim 6, wherein the current supply assembly provides the bias current to the capacitor to charge the capacitor when the energy of the light signal emitted by the ambient light source is below an energy threshold.
  9. 9. The light sensor with voltage reversal mechanism of claim 6, wherein the current supply component comprises a current source.
  10. 10. The light sensor with voltage reversal mechanism according to claim 1, characterized in that the light sensor with voltage reversal mechanism further comprises a current amplifier connected to the optoelectronic component and the capacitor and configured to amplify the second photocurrent and supply it to the capacitor for charging the capacitor.
  11. 11. The light sensor with voltage reversal mechanism according to claim 10, characterized in that the current amplifier provides the first photo-current post-amplification to the capacitor to charge the capacitor.
  12. 12. The light sensor with voltage reversal mechanism of claim 1, characterized in that the voltage reversal circuit comprises: the first end of the first switch component is connected with the photoelectric component and the first input end of the comparator, and the second end of the first switch component is connected with the first end of the capacitor; the first end of the second switch assembly is connected with the second end of the capacitor, and the second end of the second switch assembly is grounded; a third switch assembly, a first end of which is connected with the photoelectric assembly and a first input end of the comparator, a second end of which is connected with a second end of the capacitor, and A fourth switch assembly, a first end of which is connected with a first end of the capacitor, and a second end of which is grounded; when the first switch component and the second switch component are conducted, the voltage of the capacitor is charged to the first voltage; wherein when the third and fourth switching components are turned on, the voltage of the capacitor is charged from the reverse voltage of the first voltage to the second voltage.

Description

Light sensor with voltage reversal mechanism Technical Field The present invention relates to a photosensor, and more particularly, to a photosensor with a voltage reversal mechanism. Background Under different environments, the human eyes have different requirements on the screen brightness of the display screen of the electronic product. Thus, light sensors such as ambient light sensors (Ambient Light Sensor, ALS) and proximity sensors (Proximity Sensor, PS) are widely used in a variety of electronic products such as mobile devices. The light sensing value of the light sensor can be used as a basis for automatically adjusting the brightness of the display screen of the electronic device so as to improve the viewing effect in various environments. Disclosure of Invention The invention aims to solve the technical problem of providing a light sensor with a voltage reversing mechanism, which comprises a photoelectric component, a voltage reversing circuit, a comparator and a counter. The photoelectric component is configured to convert light energy of the received first light signal into a first photocurrent and provide the first photocurrent to the capacitor to charge the voltage of the capacitor to a first voltage. The voltage reversing circuit is connected with the capacitor. The voltage reversing circuit is configured to reverse the first voltage to form a reversed voltage. The first input terminal of the comparator is connected with the capacitor. The second input end of the comparator is coupled with the reference voltage. The comparator is configured to compare the first voltage with a reference voltage to output a first comparison signal. The input end of the counter is connected with the output end of the comparator. The counter is configured to count according to the first comparison signal to output a first rough estimate count value. After counting the first rough estimate value, the optoelectronic component converts the received light energy of the second light signal into a second photocurrent to be provided to the capacitor to charge the voltage of the capacitor from the reverse voltage to the second voltage. The comparator compares the second voltage with the reference voltage to output a second comparison signal. The counter counts according to the second comparison signal to output a second rough estimation value. After the second rough estimate count value is counted, the counter performs a fine count operation on the second rough estimate count value to calculate a fine count value. One of the first optical signal and the second optical signal is an optical signal reflected by the object to be detected after being emitted by both the ambient light source and the light emitting component. The other of the first optical signal and the second optical signal is an optical signal emitted by only the ambient light source. In an embodiment, the voltage reversing circuit reverses the positive first voltage to form a negative reversed voltage. The absolute value of the reverse voltage is equal to the first voltage. In an embodiment, the second photocurrent charges the voltage of the capacitor from a negative reverse voltage to a positive second voltage. In an embodiment, the light emitting assembly emits the light signal simultaneously with the ambient light source during the first phase time when the energy of the light signal emitted by the ambient light source is higher than the energy threshold, and the counter counts the first rough estimate value. After the end of the first phase time, the second phase time is entered. During a second phase time, only the ambient light source emits a light signal, and the counter counts a second rough estimate value. In an embodiment, the counter counts the first rough estimate value when the energy of the light signal emitted by the ambient light source is below the energy threshold, and only the ambient light source emits the light signal during the first phase time. After the end of the first phase time, the second phase time is entered. In a second phase time, the light emitting component emits light signals simultaneously with the ambient light source, and the counter counts a second rough estimate value. In an embodiment, the light sensor with voltage reversal mechanism further comprises a current supply component. The current supply assembly is connected with the capacitor. The current supply assembly is configured to provide a bias current to the capacitor to charge the capacitor while the second photocurrent is provided to the capacitor. In an embodiment, the current supply assembly is configured to provide a bias current to the capacitor to charge the capacitor while the first photocurrent is provided to the capacitor. In an embodiment, the current supply assembly comprises a current source. In an embodiment, the current supply assembly provides a bias current to the capacitor when the energy of the light signal emitted by the ambient light source i