Automatic re-power-on circuit based on voltage comparator

Abstract

The invention provides an automatic re-power-on circuit based on a voltage comparator, which is characterized in that the input end of each voltage comparison unit is connected to the in-phase input end of the comparator, the reverse input end of each voltage comparison unit is connected to a reference voltage for power-off comparison, and the output end of the comparator is connected to a power-off control sub-circuit through a power-off automatic recovery control sub-circuit; a triode Q16 located at the front end in the power-off control sub-circuit is connected to the output end of the power-off automatic recovery control sub-circuit, power supply voltage is connected to post-stage power supply voltage of a monitored circuit through a field-effect tube Q17 in the power-off control sub-circuit, and on-off of the field-effect tube Q17 is controlled by the triode Q16 at the front end. When a low level is input, the low level of a preset time is output, so that a triode Q16 in the power-off control sub-circuit is cut off, a field effect transistor Q17 is cut off, the post-stage power supply voltage is disconnected from the power supply voltage, and the monitored circuit connected with the post-stage power supply voltage is powered on again after being powered off for the preset time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit control, and in particular to an automatic power-on circuit based on a voltage comparator. BACKGROUND

[0002] The logic implementation of some specific integrated circuits in traditional hardware circuits is as follows: after the end of a working state, state reset needs to be performed through power-on, so as to continue normal work.

[0003] Therefore, for the integrated circuits with the above logic implementation, automatic power-on operation needs to be performed after the end of a working state, and the existing power-on technology is mostly manual operation, and the power-on operation is also relatively troublesome. SUMMARY

[0004] The present application provides an automatic power-on circuit based on a voltage comparator, so as to solve the problem that the existing circuit with power-on function needs to be manually operated and the operation mode is relatively complex.

[0005] The technical solution of the present application is as follows: the present application provides an automatic power-on circuit based on a voltage comparator, which comprises at least one voltage comparison unit and a power-off control sub-circuit. Each voltage comparison unit comprises a comparator and a power-off automatic recovery control sub-circuit connected in series, the input end of each voltage comparison unit is used for inputting a working state signal of a monitored circuit, the input end is connected to the non-inverting input end of the comparator, the inverting input end of the comparator is connected to a first reference voltage used for power-off comparison, and the output end of the comparator is connected to the power-off control sub-circuit through the power-off automatic recovery control sub-circuit. The transistor Q16 at the front end of the power-off control sub-circuit is connected to the output end of the power-off automatic recovery control sub-circuit, the power supply voltage is connected to the power supply voltage at the rear stage of the monitored circuit through the field effect transistor Q17 in the power-off control sub-circuit, and the on-off of the field effect transistor Q17 is controlled by the transistor Q16 at the front end. The automatic power-on circuit is used for outputting a low level of a preset time from the output end of the capacitor through the direct current isolation characteristic of the capacitor in the power-off control sub-circuit when the input end of each voltage comparison unit is at a low level, so that the transistor Q16 in the power-off control sub-circuit is cut off, the field effect transistor Q17 is disconnected, the power supply voltage at the rear stage is disconnected from the power supply voltage, and the monitored circuit connected to the power supply voltage at the rear stage is powered on again after power-off for a preset time.

[0006] Optionally, in the automatic power-on circuit based on a voltage comparator, the power-off control sub-circuit comprises: The power supply voltage is connected to the output terminal of the automatic power-off recovery control sub-circuit of the preceding stage via resistor 119. The power supply voltage is also connected to the base (b) of transistor Q16 via resistors 119 and R120. The collector (c) of transistor Q16 is connected to the anode of breakdown diode DZ15 via resistor R128. The cathode of diode DZ15 is connected to the power supply voltage. The emitter (e) of transistor Q16 is grounded. The anode of diode DZ15 is also connected to one end of resistor R129 and the gate (G) of MOSFET Q17. The power supply voltage is also connected to the other end of resistor R129 and the source (S) of MOSFET Q17. The drain (D) of MOSFET Q17 is connected to the power supply voltage of the subsequent stage of the monitored circuit.

[0007] Optionally, in the voltage comparator-based automatic power-on circuit described above, The power-off control sub-circuit is used to control transistor Q16 to turn off and disconnect field-effect transistor Q17 when a low level is input to its input terminal, thereby cutting off the power supply voltage and the power supply voltage of the subsequent stage used to power the monitored circuit, and de-energizing the monitored circuit connected to the subsequent stage power supply voltage. The power-off control sub-circuit is also used to control the transistor Q16 to conduct when its input terminal returns to a high level, and to make the field-effect transistor Q17 conduct after the diode DZ15 breaks down, thereby restoring the connection between the subsequent power supply voltage and the power supply voltage, and making the monitored circuit connected to the subsequent power supply voltage re-energized, that is, the monitored circuit realizes the function of automatically re-energizing after a working state ends.

[0008] Optionally, in the automatic power-on circuit based on the voltage comparator described above, the automatic power-on circuit includes: a first voltage comparison unit, the input terminal A of the first voltage comparison unit is used to input the collected voltage signal of an operating state of the monitored circuit; The first voltage comparison unit has the following structure: input terminal A is connected to the non-inverting input terminal of comparator U10A, inverting input terminal of comparator U10A is connected to the first reference voltage, and output terminal of comparator U10A is connected to the input terminal of power failure control sub-circuit via the first power failure automatic recovery control sub-circuit.

[0009] Optionally, in the voltage comparator-based automatic power-on circuit described above, The first power failure automatic recovery control sub-circuit has the following structure: resistors R114 and R115 are connected in parallel to the power supply voltage. Resistor R114 is grounded through resistor R117, and resistor R115 is grounded through resistor R118. The potential point between resistors R114 and R117 is connected to the output terminal of comparator U10A and one end of capacitor C65, respectively. The other end of capacitor C65 is connected to the non-inverting input terminal of comparator U10C after passing through the potential point between resistors R115 and R118. The inverting input terminal of comparator U10C is connected to the second reference voltage. The output terminal of comparator U10C is connected to the input terminal of the power failure control sub-circuit, and the power supply voltage is connected to the input terminal of the power failure control sub-circuit through resistor R119.

[0010] Optionally, in the automatic power-on circuit based on the voltage comparator described above, the automatic power-on circuit further includes: a second voltage comparison unit; the input terminal A of the first voltage comparison unit and the input terminal B of the second voltage comparison unit are respectively used to input the collected voltage signals of two different operating states of the monitored circuit. The second voltage comparison unit has the following structure: input terminal B is connected to the non-inverting input terminal of comparator U10B, inverting input terminal of comparator U10A is connected to the first reference voltage, and output terminal of comparator U10A is connected to the input terminal of power failure control sub-circuit via the second power failure automatic recovery control sub-circuit.

[0011] Optionally, in the voltage comparator-based automatic power-on circuit described above, The second power failure automatic recovery control sub-circuit has the following structure: resistors R124 and R125 are connected in parallel to the power supply voltage. Resistor R124 is grounded through resistor R126, and resistor R125 is grounded through resistor R127. The potential point between resistors R124 and R125 is connected to the output terminal of comparator U10B and one end of capacitor C67, respectively. The other end of capacitor C67 is connected to the non-inverting input terminal of comparator U10D after passing through the potential point between resistors R125 and R127. The inverting input terminal of comparator U10D is connected to the second reference voltage. The output terminal of comparator U10D is connected to the input terminal of the power failure control sub-circuit, and the power supply voltage is connected to the input terminal of the power failure control sub-circuit through resistor R119.

[0012] Optionally, in the voltage comparator-based automatic power-on circuit described above, for each voltage comparison unit, when the input terminal is used to input a low voltage signal of the monitored circuit, the input terminal is directly connected to the non-inverting input terminal of the corresponding comparator; when the input terminal is used to input a high voltage signal of the monitored circuit, the high voltage signal is divided by setting a voltage dividing resistor and then connected to the non-inverting input terminal of the corresponding comparator.

[0013] Optionally, in the voltage comparator-based automatic power-on circuit described above, the structure for providing the first reference voltage and the second reference voltage is as follows: The power supply voltage is grounded after passing through voltage divider resistors R123, R122, and R121. The potential point between voltage divider resistors R122 and R121 serves as the first reference voltage, which is connected to the inverting input terminals of comparators U10A and U10B, respectively. The potential point between voltage divider resistors R123 and R122 serves as the second reference voltage, which is connected to the inverting input terminals of comparators U10C and U10D, respectively.

[0014] Optionally, in the voltage comparator-based automatic power-on circuit described above, the power-off automatic recovery control sub-circuit or the second power-off automatic recovery control sub-circuit controls the power-off recovery time by setting the resistance values ​​of each resistor and the second reference voltage of the comparator. The power-off recovery time is: t = -R * C * ln((EV) / E); Where t represents the power outage recovery time, R represents the resistance value of resistor R115, C represents the capacitance value of capacitor C65 or capacitor C67, E represents the power supply voltage, and V represents the second reference voltage.

[0015] The beneficial effects of this invention are as follows: This invention provides an automatic power-on circuit based on a voltage comparator, comprising: at least one voltage comparison unit and a power-off control sub-circuit; in each voltage comparison unit, by designing the circuit structure, it collects the voltage change at the end of the previous working state of the monitored circuit, compares it with a reference voltage set by the voltage comparator, and outputs a corresponding voltage value. Utilizing the DC blocking characteristic of the capacitor in the voltage comparison unit, it outputs a brief level-flipping signal to control the field-effect transistor Q17 in the subsequent power-off control sub-circuit to briefly disconnect and then turn on, thereby achieving the required automatic power-on control. Furthermore, by changing the size of the capacitor inside the voltage comparison unit to change the power-off time of the subsequent circuit, it can adapt to different application scenarios. The automatic power-on circuit provided by this invention can not only automatically collect the voltage change at the end of the previous working state of the monitored circuit to achieve the function of automatic power-on after the end of a working state, but also allows setting different capacitor sizes to adjust the power-off time as needed. Moreover, this automatic power-on circuit has a simple structure, high reliability, and low cost, thus it is practical, easy to promote and apply, and has significant practical value. Attached Figure Description

[0016] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0017] Figure 1 A schematic diagram of the circuit structure of an automatic power-on circuit based on a voltage comparator provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the circuit structure of an automatic power-on circuit based on a voltage comparator provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the circuit structure of an automatic power-on circuit based on a voltage comparator provided in Embodiment 2 of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0019] As explained in the background section, for integrated circuits requiring a power-on reset function, their functionality necessitates a power-on reset after the end of an operating state in order to resume normal operation. Therefore, such circuits need to automatically detect and perform the power-on reset operation. However, existing circuits typically employ manual power-on operations, which are often quite complex.

[0020] To address the aforementioned problems, this invention provides an automatic power-on circuit based on a voltage comparator. This circuit has a simple structure, is easy to operate and adjust, and has high practical value.

[0021] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0022] Figure 1 A circuit diagram illustrating an automatic power-on circuit based on a voltage comparator, provided as an embodiment of the present invention, is shown below. Figure 1 As shown, the main components of the automatic power-on circuit provided in this embodiment of the invention include: at least one voltage comparison unit and a power-off control sub-circuit.

[0023] like Figure 1 In the structure of the automatic power-on circuit shown, each voltage comparison unit includes a comparator and an automatic power-off recovery control sub-circuit connected in series. The input terminal of each voltage comparison unit is used to receive the operating status signal of the monitored circuit. The input terminal is connected to the non-inverting input terminal of the comparator. The inverting input terminal of the comparator is connected to the first reference voltage used for power-off comparison. The output terminal of the comparator is connected to the power-off control sub-circuit via the automatic power-off recovery control sub-circuit.

[0024] In this embodiment of the invention, the transistor Q16 located at the front end of the power failure control sub-circuit is connected to the output terminal of the power failure automatic recovery control sub-circuit. The power supply voltage is connected to the subsequent power supply voltage of the monitored circuit through the field-effect transistor Q17 inside the power failure control sub-circuit, and the switching on and off of the field-effect transistor Q17 is controlled by the front-end transistor Q16.

[0025] Based on the circuit structure of the automatic power-on circuit in this embodiment of the invention, the working principle of the automatic power-on circuit is as follows: when the input level of each voltage comparison unit is low, the output terminal of the capacitor in the power-off control sub-circuit outputs a low level for a preset time through the DC blocking characteristic of the capacitor, so that the transistor Q16 in the power-off control sub-circuit is cut off, thereby disconnecting the field-effect transistor Q17, so that the power supply voltage of the subsequent stage is disconnected from the power supply voltage, thereby enabling the monitored circuit connected to the power supply voltage of the subsequent stage to achieve power-on after a preset time of power-off.

[0026] It should be noted that, in the embodiments of the present invention, the monitored circuit refers to a circuit that, after the end of a working state, needs to be re-energized for state reset in order to continue normal operation; that is, the power-off and power-on objects of the automatic power-on circuit provided in the embodiments of the present invention are the monitored circuits. The monitoring terminals of the working state of the monitored circuits can be one or more. If there is only one monitoring terminal, then one voltage comparison unit can be designed in the automatic power-on circuit. The monitoring terminal is connected to the input terminal of the voltage comparison unit. If the monitored circuits have multiple monitoring terminals, then a corresponding number of voltage comparison units can be set for the automatic power-on circuits.

[0027] In one implementation of this invention, such as Figure 1 As shown, the power-off control sub-circuit includes: The power supply voltage is connected to the output terminal of the pre-stage power failure automatic recovery control sub-circuit via resistor 119, and is also connected to the base (b) of transistor Q16 via resistors 119 and R120. The collector (c) of transistor Q16 is connected to the anode of breakdown diode DZ15 via resistor R128, and the cathode of diode DZ15 is connected to the power supply voltage. The emitter (e) of transistor Q16 is grounded, and the anode of diode DZ15 is also connected to one end of resistor R129 and the gate (G) of MOSFET Q17. The power supply voltage is also connected to the other end of resistor R129 and the source (S) of MOSFET Q17. The drain (D) of MOSFET Q17 is connected to the power supply voltage of the subsequent stage of the monitored circuit.

[0028] Based on the specific circuit structure of the power-off control sub-circuit in this implementation method, the working principle of the power-off control sub-circuit is as follows: When a low level is input to its input terminal, the control transistor Q16 is turned off, and the field-effect transistor Q17 is disconnected, thereby cutting off the power supply voltage and the power supply voltage used to power the monitored circuit, and de-energizing the monitored circuit connected to the power supply voltage. When the input returns to a high level, the control transistor Q16 turns on, and the diode DZ15 breaks down, causing the field-effect transistor Q17 to turn on. This restores the connection between the power supply voltage and the power source voltage, and also re-energizes the monitored circuit connected to the power supply voltage. In other words, the monitored circuit achieves the function of automatically re-energizing after the end of a working state.

[0029] It should be noted that in this implementation, the voltage signal at the input terminal of the interruption control sub-circuit is provided by at least one voltage comparison unit connected to it. The voltage signal is provided based on the change in the operating state of the monitored circuit. When a working state of the monitored circuit ends, a low level is input to the input terminal of the voltage comparison unit to disconnect the power supply voltage of the subsequent stage and thus power off the monitored circuit. In addition, based on the setting of the automatic power-off recovery control sub-circuit inside the voltage comparison unit, after a certain period of power failure, the voltage at the input terminal of the power failure control sub-circuit flips and is powered on again by charging the capacitor. That is, the subsequent monitored circuit is powered on again after a preset power failure time.

[0030] The automatic power-on circuit based on a voltage comparator provided in this invention includes at least one voltage comparison unit and a power-off control sub-circuit. Each voltage comparison unit, through circuit structure design, collects the voltage change at the end of the previous operating state of the monitored circuit, compares it with a reference voltage set by the voltage comparator, and outputs a corresponding voltage value. Utilizing the DC blocking characteristic of the capacitor in the voltage comparison unit, a brief level-flipping signal is output to control the short-term disconnection and subsequent reconnection of the field-effect transistor Q17 in the subsequent power-off control sub-circuit, thereby achieving the required automatic power-on control. Furthermore, by changing the size of the capacitor inside the voltage comparison unit to change the power-off time of the subsequent circuit, it can adapt to different application scenarios. Using the automatic power-on circuit provided in this invention, not only can the automatic collection of the voltage change at the end of the previous operating state of the monitored circuit achieve the function of automatic power-on after the end of an operating state, but different capacitor sizes can also be set to adjust the power-off time as needed. Moreover, this automatic power-on circuit has a simple structure, high reliability, and low cost, thus possessing good practicality, easy promotion and application, and significant practical value.

[0031] The following specific embodiments illustrate the implementation of the automatic power-on circuit based on a voltage comparator provided in this invention.

[0032] Example 1 Figure 2 This is a schematic diagram of the circuit structure of an automatic power-on circuit based on a voltage comparator provided in Embodiment 1 of the present invention. (Refer to...) Figure 1 As shown, the main components of the automatic power-on circuit based on a voltage comparator provided in this embodiment of the invention include: a voltage comparison unit and a power-off control sub-circuit.

[0033] like Figure 2 As shown, the circuit structure and working principle of the interrupt control sub-circuit in this embodiment 1 are the same as those in embodiment 1. In this embodiment 1, only one voltage comparison unit is set, namely the first voltage comparison unit. The input terminal A of the first voltage comparison unit is used to input the collected voltage signal of a working state of the monitored circuit.

[0034] In this embodiment 1, the structure of the first voltage comparison unit is as follows: the input terminal A is connected to the non-inverting input terminal of comparator U10A, the inverting input terminal of comparator U10A is connected to the first reference voltage, and the output terminal of comparator U10A is connected to the input terminal of the power failure control sub-circuit via the first power failure automatic recovery control sub-circuit.

[0035] In this embodiment 1, the structure of the first power failure automatic recovery control sub-circuit in the first voltage comparison unit is as follows: resistors R114 and R115 are connected in parallel to the power supply voltage. Resistor R114 is grounded through resistor R117, and resistor R115 is grounded through resistor R118. The potential point between resistors R114 and R117 is connected to the output terminal of comparator U10A and one end of capacitor C65, respectively. The other end of capacitor C65 is connected to the non-inverting input terminal of comparator U10C after passing through the potential point between resistors R115 and R118. The inverting input terminal of comparator U10C is connected to the second reference voltage. The output terminal of comparator U10C is connected to the input terminal of the power failure control sub-circuit, and the power supply voltage is connected to the input terminal of the power failure control sub-circuit through resistor R119.

[0036] It should be noted that in the first voltage comparison unit, the first reference voltage connected to comparator U10A is the power-off comparison voltage of the monitored circuit's operating state monitored through input terminal A. That is, when the voltage input to input terminal A is lower than the first reference voltage, the voltage at input terminal E of the subsequent power-off control sub-circuit is pulled down to cut off the subsequent power supply voltage of the monitored circuit. The second reference voltage is the recovery comparison voltage. That is, when the voltage at input terminal A is pulled down, the voltage will slowly rise through the charging process of capacitor C65. When the voltage rises to exceed the second reference voltage of comparator U10C, its back-end voltage is flipped to a high level, so that the subsequent power supply voltage of the monitored circuit is reconnected to the voltage.

[0037] Example 2 Figure 2This is a schematic diagram of the circuit structure of an automatic power-on circuit based on a voltage comparator provided in Embodiment 2 of the present invention; see also Figure 2 As shown, the automatic power-on circuit provided in Embodiment 2 has the same structure and circuit function as the circuit provided in Embodiment 1. The difference is that Embodiment 2 has two voltage comparison units, that is, in addition to Embodiment 1, it also has a second voltage comparison unit. In Embodiment 2, the input terminal A of the first voltage comparison unit and the input terminal B of the second voltage comparison unit are used to input the collected voltage signals of the monitored circuit in two different operating states, respectively.

[0038] In this embodiment 2, the structure of the second voltage comparison unit is similar to that of the first voltage comparison unit. Specifically, the input terminal B is connected to the non-inverting input terminal of comparator U10B, the inverting input terminal of comparator U10A is connected to the first reference voltage, and the output terminal of comparator U10A is connected to the input terminal of the power failure control sub-circuit via the second power failure automatic recovery control sub-circuit.

[0039] In this embodiment 2, the structure of the second power failure automatic recovery control sub-circuit is basically similar to that of the first power failure automatic recovery control sub-circuit. Specifically, resistors R124 and R125 are connected in parallel to the power supply voltage. Resistor R124 is grounded through resistor R126, and resistor R125 is grounded through resistor R127. The potential point between resistors R124 and R125 is connected to the output terminal of comparator U10B and one end of capacitor C67, respectively. The other end of capacitor C67 is connected to the non-inverting input terminal of comparator U10D after passing through the potential point between resistors R125 and R127. The inverting input terminal of comparator U10D is connected to the second reference voltage. The output terminal of comparator U10D is connected to the input terminal of the power failure control sub-circuit, and the power supply voltage is connected to the input terminal of the power failure control sub-circuit through resistor R119.

[0040] In this embodiment 2, the input terminals A and B of the two voltage comparison units are the acquisition points for judging different working states of the monitored circuit. The input is a voltage signal. By comparing the voltage magnitude at points A and B with the first reference voltage, the timing of automatic power-on is determined. When automatic power-on is required, the comparator U10A or U10B outputs a low-level signal. Utilizing the DC blocking characteristic of the capacitor, a brief low level will be generated at point C or D after capacitor C65 or capacitor C67 (the duration of the low level is set by the size of capacitor C65 or capacitor C67). Then, a brief low-level signal will be output at point E.

[0041] When point E is low, transistor Q16 is cut off, MOSFET Q17 is disconnected, the subsequent power supply voltage RE_+12V is disconnected from the power supply voltage +12V, and the monitored circuit connected to RE_+12V will be disconnected from the power supply voltage +12V. When point E returns to a high level, Q16 conducts. After the breakdown diode DZ15 breaks down, Q17 is ensured to conduct, and RE_+12V is reconnected to +12V. The subsequent circuit connected to RE_+12V will then be reconnected to the power supply +12V, realizing the function of automatically repowering after a working state ends.

[0042] Based on Embodiments 1 and 2 of the present invention, for each voltage comparison unit, when the input terminal is used to input a low voltage signal from the monitored circuit, the input terminal is directly connected to the non-inverting input terminal of the corresponding comparator, such as... Figure 3 The input terminal B of the second voltage comparison unit is directly connected to the non-inverting input terminal of comparator U10B; when the input terminal is used to input a high-voltage signal from the monitored circuit, the high-voltage signal is divided by a voltage divider resistor and then connected to the non-inverting input terminal of the corresponding comparator, such as... Figure 2 As shown, the potential point collected by the input terminal A of the first voltage comparison unit is a high voltage signal. Therefore, the input terminal A is grounded after passing through the voltage divider resistors R113 and R116. The potential point between the voltage divider resistors R113 and R116 is connected to the non-inverting input terminal of the comparator U10A.

[0043] Based on the above embodiments 1 and 2 of the present invention, the structure for providing the first reference voltage and the second reference voltage is as follows: the power supply voltage is grounded after passing through voltage divider resistors R123, R122 and R121; the potential point between voltage divider resistors R122 and R121 serves as the first reference voltage and is connected to the inverting input terminals of comparators U10A and U10B respectively; the potential point between voltage divider resistors R123 and R122 serves as the second reference voltage and is connected to the inverting input terminals of comparators U10C and U10D respectively.

[0044] It should be noted that in each voltage comparison unit of this embodiment, under the premise that the voltage across capacitor C65 or C67 is equal when U10A and U10B output a high level, the resistance values ​​of resistor network R114, R115, R117, R118 (or R124, R125, R126, R127) are fixed. The power-off recovery time is set by setting the size of capacitor C65 or capacitor C67, which can be set according to actual needs.

[0045] The following example, using the first voltage comparison unit, illustrates the design method for the power outage recovery time in this embodiment of the invention, calculated according to the following formula: t = -R * C * ln((EV) / E); Where t represents the power outage recovery time, with resistors R114 = R115 = 6.8kΩ, resistors R117 = R118 = 4.7kΩ, power supply voltage E = 12V, capacitor C65 is 10uF, and the second reference comparison voltage of comparator U10C is set to V = 4V. Substituting these values ​​into the above formula, the power outage recovery time t = 27ms is calculated. To reduce the variation in delay time across the entire temperature range, a ceramic capacitor with stable temperature characteristics and small capacitance value deviation is selected.

[0046] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An automatic power-on circuit based on a voltage comparator, characterized in that, include: At least one voltage comparison unit and a power-off control sub-circuit; Each voltage comparison unit includes a comparator and an automatic power failure recovery control sub-circuit connected in series. The input terminal of each voltage comparison unit is used to receive the operating status signal of the monitored circuit. The input terminal is connected to the non-inverting input terminal of the comparator. The inverting input terminal of the comparator is connected to the first reference voltage for power failure comparison. The output terminal of the comparator is connected to the power failure control sub-circuit via the automatic power failure recovery control sub-circuit. In the power failure control sub-circuit, the transistor Q16 at the front end is connected to the output terminal of the power failure automatic recovery control sub-circuit. The power supply voltage is connected to the subsequent power supply voltage of the monitored circuit through the field effect transistor Q17 inside the power failure control sub-circuit, and the switching on and off of the field effect transistor Q17 is controlled by the transistor Q16 at the front end. The automatic power-on circuit is used to output a low level for a preset time by utilizing the DC blocking characteristic of the capacitor in the power-off control sub-circuit when the input level of each voltage comparison unit is low. This causes the transistor Q16 in the power-off control sub-circuit to be cut off, thereby disconnecting the field-effect transistor Q17. This disconnects the subsequent power supply voltage from the power supply voltage, allowing the monitored circuit connected to the subsequent power supply voltage to achieve power-on after a preset time of power-off.

2. The automatic power-on circuit based on a voltage comparator according to claim 1, characterized in that, The power-off control sub-circuit includes: The power supply voltage is connected to the output terminal of the automatic power-off recovery control sub-circuit of the preceding stage via resistor 119. The power supply voltage is also connected to the base (b) of transistor Q16 via resistors 119 and R120. The collector (c) of transistor Q16 is connected to the anode of breakdown diode DZ15 via resistor R128. The cathode of diode DZ15 is connected to the power supply voltage. The emitter (e) of transistor Q16 is grounded. The anode of diode DZ15 is also connected to one end of resistor R129 and the gate (G) of MOSFET Q17. The power supply voltage is also connected to the other end of resistor R129 and the source (S) of MOSFET Q17. The drain (D) of MOSFET Q17 is connected to the power supply voltage of the subsequent stage of the monitored circuit.

3. The automatic power-on circuit based on a voltage comparator according to claim 2, characterized in that, The power-off control sub-circuit is used to control transistor Q16 to turn off and disconnect field-effect transistor Q17 when a low level is input to its input terminal, thereby cutting off the power supply voltage and the power supply voltage of the subsequent stage used to power the monitored circuit, and de-energizing the monitored circuit connected to the subsequent stage power supply voltage. The power-off control sub-circuit is also used to control the transistor Q16 to conduct when its input terminal returns to a high level, and to make the field-effect transistor Q17 conduct after the diode DZ15 breaks down, thereby restoring the connection between the subsequent power supply voltage and the power supply voltage, and making the monitored circuit connected to the subsequent power supply voltage re-energized, that is, the monitored circuit realizes the function of automatically re-energizing after a working state ends.

4. The automatic power-on circuit based on a voltage comparator according to any one of claims 1 to 3, characterized in that, The automatic power-on circuit includes: a first voltage comparison unit, wherein the input terminal A of the first voltage comparison unit is used to input the collected voltage signal of a working state of the monitored circuit; The first voltage comparison unit has the following structure: input terminal A is connected to the non-inverting input terminal of comparator U10A, inverting input terminal of comparator U10A is connected to the first reference voltage, and output terminal of comparator U10A is connected to the input terminal of power failure control sub-circuit via the first power failure automatic recovery control sub-circuit.

5. The automatic power-on circuit based on a voltage comparator according to claim 4, characterized in that, The first power failure automatic recovery control sub-circuit has the following structure: resistors R114 and R115 are connected in parallel to the power supply voltage. Resistor R114 is grounded through resistor R117, and resistor R115 is grounded through resistor R118. The potential point between resistors R114 and R117 is connected to the output terminal of comparator U10A and one end of capacitor C65, respectively. The other end of capacitor C65 is connected to the non-inverting input terminal of comparator U10C after passing through the potential point between resistors R115 and R118. The inverting input terminal of comparator U10C is connected to the second reference voltage. The output terminal of comparator U10C is connected to the input terminal of the power failure control sub-circuit, and the power supply voltage is connected to the input terminal of the power failure control sub-circuit through resistor R119.

6. The automatic power-on circuit based on a voltage comparator according to claim 5, characterized in that, The automatic power-on circuit also includes: a second voltage comparison unit; the input terminal A of the first voltage comparison unit and the input terminal B of the second voltage comparison unit are respectively used to input the collected voltage signals of two different operating states of the monitored circuit. The second voltage comparison unit has the following structure: input terminal B is connected to the non-inverting input terminal of comparator U10B, inverting input terminal of comparator U10A is connected to the first reference voltage, and output terminal of comparator U10A is connected to the input terminal of power failure control sub-circuit via the second power failure automatic recovery control sub-circuit.

7. The automatic power-on circuit based on a voltage comparator according to claim 6, characterized in that, The second power failure automatic recovery control sub-circuit has the following structure: resistors R124 and R125 are connected in parallel to the power supply voltage. Resistor R124 is grounded through resistor R126, and resistor R125 is grounded through resistor R127. The potential point between resistors R124 and R125 is connected to the output terminal of comparator U10B and one end of capacitor C67, respectively. The other end of capacitor C67 is connected to the non-inverting input terminal of comparator U10D after passing through the potential point between resistors R125 and R127. The inverting input terminal of comparator U10D is connected to the second reference voltage. The output terminal of comparator U10D is connected to the input terminal of the power failure control sub-circuit, and the power supply voltage is connected to the input terminal of the power failure control sub-circuit through resistor R119.

8. The automatic power-on circuit based on a voltage comparator according to claim 6, characterized in that, For each voltage comparison unit, when the input terminal is used to input a low voltage signal of the monitored circuit, the input terminal is directly connected to the non-inverting input terminal of the corresponding comparator; when the input terminal is used to input a high voltage signal of the monitored circuit, the high voltage signal is divided by setting a voltage dividing resistor and then connected to the non-inverting input terminal of the corresponding comparator.

9. The automatic power-on circuit based on a voltage comparator according to claim 6, characterized in that, The structure used to provide the first reference voltage and the second reference voltage is as follows: The power supply voltage is grounded after passing through voltage divider resistors R123, R122, and R121. The potential point between voltage divider resistors R122 and R121 serves as the first reference voltage, which is connected to the inverting input terminals of comparators U10A and U10B, respectively. The potential point between voltage divider resistors R123 and R122 serves as the second reference voltage, which is connected to the inverting input terminals of comparators U10C and U10D, respectively.

10. The automatic power-on circuit based on a voltage comparator according to claim 7, characterized in that, In either the first or second automatic power failure recovery control sub-circuit, the power failure recovery time is controlled by setting the resistance values ​​of each resistor and the second reference voltage of the comparator. The power failure recovery time is: t = -R * C * ln((EV) / E); Where t represents the power outage recovery time, R represents the resistance value of resistor R115, C represents the capacitance value of capacitor C65 or capacitor C67, E represents the power supply voltage, and V represents the second reference voltage.

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