Hysteresis circuit, emergency lighting circuit and lighting device

Patent metadata

Field	Value
Publication number	US-12588125-B2
Application number	US-202418437535-A
Country	US
Kind code	B2
Filing date	Feb 9, 2024
Priority date	Aug 16, 2021
Publication date	Mar 24, 2026
Grant date	Mar 24, 2026

Abstract

The present disclosure discloses a hysteresis circuit, an emergency lighting circuit, and a lighting device. The hysteresis circuit includes a voltage detection module, an isolation coupling module, and a voltage adjusting module. By detecting the sampling voltage associated with the input voltage, in the case that the sampling voltage is detected to decrease to the trigger action voltage point, the corresponding level of the output signal flips until it is detected that the sampling voltage rises to the reverse recovery voltage point, and the corresponding level of the output signal is controlled to flip again, thus achieving timely and accurate judgment of input voltage status.

First claim

The invention claimed is:

1 . A hysteresis circuit, comprising:
a voltage detection module, configured to receive an input voltage and generate a sampling voltage based on the input voltage, and detect the sampling voltage, wherein the voltage detection module comprises: one or more first voltage divider resistor, a second voltage divider resistor, a first capacitor, and a voltage regulator, wherein the one or more first voltage divider resistor is connected to the second voltage divider resistor to form a first node, the one or more first voltage divider resistor and the second voltage divider resistor are configured to divide the input voltage so that a voltage of the first node is the sampling voltage, the second voltage divider resistor is electrically connected to the first capacitor and the voltage regulator, and the voltage regulator is configured to obtain the sampling voltage; an isolation coupling module, wherein the isolation coupling module is connected to the voltage regulator and configured to control an output signal of the isolation coupling module based on the sampling voltage; and a voltage adjusting module, configured to adjust the sampling voltage; wherein in a case that the voltage detection module detects that the sampling voltage is less than a first set value, an optocoupler in the isolation coupling module is controlled to be in an isolating state, so that the output signal of the isolation coupling module is a first level signal, and the voltage adjusting module begins to adjust the sampling voltage; in a case that the voltage detection module detects that the sampling voltage is greater than a second set value, the optocoupler is controlled to be in a coupling state, so that the output signal of the isolation coupling module is a second level signal, and the voltage adjusting module stops adjusting the sampling voltage, the second set value is greater than the first set value, and a difference between the second set value and the first set value is greater than a preset threshold, the first level signal is different from the second level signal.

2 . The hysteresis circuit according to claim 1 , wherein:
the one or more first voltage divider resistor comprises a first resistor, a second resistor, and a third resistor, and the second voltage divider resistor is a fourth resistor; a first end of the one or more first voltage divider resistor receives the input voltage, and a second end of the one or more first voltage divider resistor is connected to a first end of the second voltage divider resistor to form the first node, the first end of the second voltage divider resistor is electrically connected to a first end of the first capacitor and a first pin of the voltage regulator, and a second end of the second voltage divider resistor is electrically connected to a second end of the first capacitor and a third pin of the voltage regulator, respectively; the first end of the first capacitor is electrically connected to the first pin of the voltage regulator, and the second end of the first capacitor is electrically connected to the third pin of the voltage regulator; a second pin of the voltage regulator is connected to the isolation coupling module, the third pin of the voltage regulator is connected to a power ground, and the first pin of the voltage regulator is configured to obtain the sampling voltage.

3 . The hysteresis circuit according to claim 2 , wherein:
in a case that the sampling voltage obtained by the first pin of the voltage regulator is less than the first set value, the voltage regulator is in a cut-off state; in a case that the sampling voltage obtained by the first pin of the voltage regulator is greater than the second set value, the voltage regulator is in a conductive state.

4 . The hysteresis circuit according to claim 2 , wherein:
the isolation coupling module further comprises: a fifth resistor and a sixth resistor; a first end of the fifth resistor receives a first side supply voltage, and a second end of the fifth resistor is electrically connected to a positive electrode of a light-emitting diode on a primary side of the optocoupler; a first end of the sixth resistor is connected to a second side supply voltage, and a second end of the sixth resistor is electrically connected to a collector electrode of a triode on a secondary side of the optocoupler; a negative electrode of the light-emitting diode on the primary side of the optocoupler is electrically connected to a second pin of the voltage regulator in the voltage detection module, and an emitter electrode of the triode on the secondary side of the optocoupler is connected to a signal ground.

5 . The hysteresis circuit according to claim 4 , wherein:
the voltage adjusting module comprises: a first voltage stabilizing transistor, a seventh resistor, an eighth resistor, a ninth resistor, and a first switching transistor; a first end of the first voltage stabilizing transistor is electrically connected to a first end of the seventh resistor, and a second end of the first voltage stabilizing transistor is electrically connected to a second end of the fifth resistor in the isolation coupling module; a second end of the seventh resistor is electrically connected to a first end of the eighth resistor and a control end of the first switching transistor, respectively; a first end of the eighth resistor is electrically connected to a control end of the first switching transistor, and a second end of the eighth resistor is electrically connected to a first end of the first switching transistor; a first end of the ninth resistor is electrically connected to a first end of a second voltage divider resistor in the voltage detection module, and a second end of the ninth resistor is electrically connected to a second end of the first switching transistor; a first end of the first switching transistor is respectively connected to a second end of the second voltage divider resistor in the voltage detection module and a power ground.

6 . The hysteresis circuit according to claim 5 , wherein:
a second voltage divider resistor in the voltage detection module and a ninth resistor in the voltage adjusting module are variable resistors.

7 . The hysteresis circuit according to claim 6 , wherein:
the first set value is configured to be associated with a resistance value of the second divider resistor; and the second set value is configured to be associated with a resistance value of the ninth resistor.

8 . The hysteresis circuit according to claim 1 , wherein:
a power ground connected to a voltage regulator in the voltage detection module on a primary side of the optocoupler is not in common ground with a signal ground connected to the secondary side of the optocoupler.

9 . An emergency lighting circuit, comprising:
a rectification circuit, configured to convert an input AC power into a DC power to provide the DC power to the hysteresis circuit; a hysteresis circuit that comprises: a voltage detection module, configured to receive an input voltage and generate a sampling voltage based on the input voltage, and detect the sampling voltage, wherein the voltage detection module comprises: one or more first voltage divider resistor, a second voltage divider resistor, a first capacitor, and a voltage regulator, wherein the one or more first voltage divider resistor is connected to the second voltage divider resistor to form a first node, the one or more first voltage divider resistor and the second voltage divider resistor are configured to divide the input voltage so that a voltage of the first node is the sampling voltage, the second voltage divider resistor is electrically connected to the first capacitor and the voltage regulator, and the v

Assignees

• Opple Lighting Co Ltd
• Suzhou opple lighting co ltd

Inventors

• Liu Xinsheng
• Zhu Guangchuan

Classifications

• H05B47/14 Primary

  by determining electrical parameters of the light source · CPC title