Two-way standby circuit for RTC power supply

Abstract

The utility model provides a dual-path standby circuit for RTC power supply. The dual-path standby circuit comprises a direct power supply circuit, a capacitor power supply circuit, a capacitor module and a dual-channel power supply selection circuit, the first input end of the dual-channel power supply selection circuit is electrically connected to the direct power supply circuit, the second input end of the dual-channel power supply selection circuit is electrically connected to the output end of the capacitor module, and the output end of the dual-channel power supply selection circuit is electrically connected to the RTC; the input end of the capacitor module is electrically connected to the output end of the capacitor power supply circuit. According to the double-channel standby circuit, the direct power supply circuit and the standby power supply circuit are connected through the double-channel power supply selection circuit, when direct power supply is lost, the standby power supply circuit continues to work, and the reliability of RTC power supply is improved; in addition, the standby power supply circuit uses a voltage reference chip, has the advantages of small size, simple layout and low price, and can effectively reduce the cost.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a dual-channel backup circuit for RTC power supply. Background Art

[0002] An RTC (Real-Time Clock) can provide a stable clock signal. The RTC is a key time management device in various applications, used to track time, synchronize clocks, provide timing and timekeeping functions, and provide accurate time stamps for data recording and event scheduling.

[0003] The existing RTC power supplies are usually as follows: (1) single-channel power supply is adopted, and when the main power supply is cut off or unavailable, the RTC cannot work, which may lead to problems such as incorrect recording of fault event time; (2) dual-channel power supply is adopted, that is, a backup power supply (a disposable battery or a rechargeable battery) is added. When the main power supply is cut off or unavailable, the RTC uses the backup power supply to continue calculating time. When the backup power supply runs out of power or has insufficient power, it is necessary to manually replace the disposable battery, use a DC-DC power converter or an LDO (Low Dropout Regulator) to charge the battery, with low reliability and high cost. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a dual-channel backup circuit for RTC power supply, so as to solve at least the technical problems of low reliability and high cost of the existing RTC power supply.

[0005] The utility model provides a dual-channel backup circuit for RTC power supply, including: a direct power supply circuit, a capacitor power supply circuit, a capacitor module and a dual-channel power supply selection circuit; the first input end of the dual-channel power supply selection circuit is electrically connected to the direct power supply circuit, the second input end of the dual-channel power supply selection circuit is electrically connected to the output end of the capacitor module, the output end of the dual-channel power supply selection circuit is electrically connected to the RTC; the input end of the capacitor module is electrically connected to the output end of the capacitor power supply circuit.

[0006] Preferably, the direct power supply circuit includes: a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and an LDO chip; the LDO chip includes: a voltage input pin, a voltage output pin and a ground pin; one end of the parallel connection of the first capacitor and the second capacitor is electrically connected to the +5V power supply voltage and the voltage input pin, and the other end is grounded; one end of the parallel connection of the third capacitor and the fourth capacitor is electrically connected to the voltage output pin and the first input end of the dual-channel power supply selection circuit, and the other end is grounded; the ground pin is grounded.

[0007] Preferably, the capacitor power supply circuit includes: a triode, a first resistor, a second resistor, a third resistor, a fifth capacitor, a sixth capacitor, and a voltage reference chip; one end of the fifth capacitor and the sixth capacitor in parallel, one end of the first resistor, and the collector of the triode are all electrically connected to the +5V power supply voltage; the base of the triode is electrically connected to the other end of the first resistor and the cathode of the voltage reference chip, and the emitter of the triode is electrically connected to one end of the second resistor and serves as the output end of the capacitor power supply circuit; the reference pin of the voltage reference chip is electrically connected to the other end of the second resistor and one end of the third resistor; the other end of the fifth capacitor and the sixth capacitor in parallel, the anode of the voltage reference chip, and the other end of the third resistor are all grounded.

[0008] Preferably, the dual-channel power supply selection circuit includes: a first diode and a second diode; the positive electrode of the first diode is the first input end of the dual-channel power supply selection circuit, the positive electrode of the second diode is the second input end of the dual-channel power supply selection circuit, and the negative electrodes of the first diode and the second diode are electrically connected and serve as the output end of the dual-channel power supply selection circuit.

[0009] Preferably, it further includes: a filtering circuit; the input end of the filtering circuit is electrically connected to the output end of the dual-channel power supply selection circuit, and the output end of the filtering circuit is electrically connected to the RTC.

[0010] Preferably, the filtering circuit includes: a seventh capacitor and an eighth capacitor in parallel.

[0011] Preferably, one end of the seventh capacitor is the input end of the filtering circuit, one end of the eighth capacitor is the output end of the filtering circuit, and the other ends of the seventh capacitor and the eighth capacitor are electrically connected and grounded.

[0012] Preferably, the capacitor module includes: a ninth capacitor and a tenth capacitor in parallel.

[0013] Preferably, both the ninth capacitor and the tenth capacitor are lithium-ion capacitors; the positive electrode of the ninth capacitor is the input end of the capacitor module, the positive electrode of the tenth capacitor is the output end of the capacitor module, and the negative electrodes of the ninth capacitor and the tenth capacitor are electrically connected and grounded.

[0014] Preferably, the output end of the dual-channel power supply selection circuit outputs a 3.3V voltage.

[0015] The dual-channel backup circuit for RTC power supply provided by the present utility model electrically connects a capacitor power supply circuit and a capacitor module as a backup power supply circuit, and connects a direct power supply circuit and the backup power supply circuit through a dual-channel power supply selection circuit. When the direct power supply is lost, the backup power supply circuit works, improving the reliability of RTC power supply; in addition, the voltage reference chip used in the backup power supply circuit has the advantages of small volume, simple layout and low price, which can effectively reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 It is a structural block diagram of the dual-channel backup circuit for RTC power supply according to an embodiment of the present utility model.

[0018] Figure 2 It is a schematic diagram of the dual-channel backup circuit for RTC power supply according to an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] In order to make the above objects, features and advantages of the present utility model more obvious and understandable, the following will make a detailed description of the specific embodiments of the present utility model in conjunction with the drawings. It should be understood that many specific details are set forth in the following description in order to fully understand the present utility model, but the present utility model can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present utility model, so the present utility model is not limited by the specific embodiments disclosed below.

[0020] As Figure 1 shown, this embodiment provides a dual-channel backup circuit for RTC power supply, including: a direct power supply circuit 1, a capacitor power supply circuit 2, a capacitor module 3 and a dual-channel power supply selection circuit 4.

[0021] The first input terminal of the dual-channel power supply selection circuit 4 is electrically connected to the direct power supply circuit 1, the second input terminal of the dual-channel power supply selection circuit 4 is electrically connected to the output terminal of the capacitor module 3, and the output terminal of the dual-channel power supply selection circuit 4 is electrically connected to the RTC; the input terminal of the capacitor module 3 is electrically connected to the output terminal of the capacitor power supply circuit 2.

[0022] Here, after the capacitor power supply circuit 2 and the capacitor module 3 are electrically connected, they serve as a backup power supply circuit. This backup power supply circuit is electrically connected to the direct power supply circuit 1 through a dual-channel power supply selection circuit 4 to form a dual-channel backup circuit for RTC power supply.

[0023] As an example, the output terminal of the dual-channel power supply selection circuit 4 outputs a 3.3V voltage 3V3_RTC for RTC power supply.

[0024] Preferably, the dual-channel backup circuit further includes: a filter circuit 5.

[0025] The input terminal of the filter circuit 5 is electrically connected to the output terminal of the dual-channel power supply selection circuit 4, and the output terminal of the filter circuit 5 is electrically connected to the RTC.

[0026] The filter circuit 5 is used to filter the 3.3V voltage output by the dual-channel power supply selection circuit 4, which can filter out high-frequency signals and interference signals, significantly improve the voltage stability, and then provide a stable power supply voltage for the RTC.

[0027] As Figure 2 shown, the dual-channel power supply selection circuit 4 includes: a first diode D1 and a second diode D2.

[0028] The positive electrode of the first diode D1 is the first input terminal of the dual-channel power supply selection circuit 4, the positive electrode of the second diode D2 is the second input terminal of the dual-channel power supply selection circuit 4, and the negative electrodes of the first diode D1 and the second diode D2 are electrically connected and used as the output terminal of the dual-channel power supply selection circuit 4.

[0029] Preferably, the direct power supply circuit 1 includes: a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, and an LDO chip U1.

[0030] The LDO chip U1 includes: a voltage input pin Vin, a voltage output pin Vout, and a ground pin; the ground pin is grounded to GND.

[0031] One end after the first capacitor C1 and the second capacitor C2 are connected in parallel is electrically connected to the +5V power supply voltage and the voltage input pin Vin, and the other end is grounded to GND.

[0032] One end after the third capacitor C3 and the fourth capacitor C4 are connected in parallel is electrically connected to the voltage output pin Vout and the positive electrode of the first diode D1, and the other end is grounded to GND.

[0033] Preferably, the capacitor power supply circuit 2 includes: a triode Q1, a first resistor R1, a second resistor R2, a third resistor R3, a fifth capacitor C5, a sixth capacitor C6, and a voltage reference chip U2.

[0034] One end of the fifth capacitor C5 and the sixth capacitor C6 after being connected in parallel, one end of the first resistor R1, and the collector of the triode Q1 are all electrically connected to the +5V power supply voltage.

[0035] The base of the triode Q1 is electrically connected to the other end of the first resistor R1 and the cathode of the voltage reference chip U2, and the emitter of the triode Q1 is electrically connected to one end of the second resistor R2 and serves as the output end of the capacitor power supply circuit 2.

[0036] The reference pin of the voltage reference chip U2 is electrically connected to the other end of the second resistor R2 and one end of the third resistor R3.

[0037] The other end of the fifth capacitor C5 and the sixth capacitor C6 after being connected in parallel, the anode of the voltage reference chip U2, and the other end of the third resistor R3 are all grounded to GND.

[0038] Here, the voltage reference chip U2 has the advantages of small volume, simple layout, and low price, and can effectively reduce costs.

[0039] Preferably, the capacitor module 3 includes: a ninth capacitor C9 and a tenth capacitor C10.

[0040] As an example, both the ninth capacitor C9 and the tenth capacitor C10 are lithium-ion capacitors.

[0041] The ninth capacitor C9 and the tenth capacitor C10 are connected in parallel; the positive electrode of the ninth capacitor C9 is the input end of the capacitor module 3; the positive electrode of the tenth capacitor C10 serves as the output end of the capacitor module 3 and is electrically connected to the positive electrode of the second diode D2; the negative electrode of the ninth capacitor C9 is electrically connected to the negative electrode of the tenth capacitor C10 and then grounded to GND.

[0042] Preferably, the filter circuit 5 includes: a seventh capacitor C7 and an eighth capacitor C8.

[0043] The seventh capacitor C7 and the eighth capacitor C8 are connected in parallel; one end of the seventh capacitor C7 serves as the input end of the filter circuit 5 and is electrically connected to the negative electrode of the first diode D1 and the negative electrode of the second diode D2; one end of the eighth capacitor C8 serves as the output end of the filter circuit 5 and is electrically connected to the RTC; the other end of the seventh capacitor C7 is electrically connected to the other end of the eighth capacitor C8 and then grounded.

[0044] The working process of the dual-channel backup circuit in this embodiment is as follows: Under normal circumstances, the first diode D1 is conducting and the second diode D2 is cut off, and the direct power supply circuit 1 supplies power to the RTC; when the direct power supply circuit 1 is abnormal, that is, when the direct power supply is lost, the first diode D1 is cut off and the second diode D2 is conducting, and the backup power supply circuit works normally and continues to supply power to the RTC, effectively improving the reliability of the RTC power supply.

[0045] The dual-channel backup circuit for RTC power supply provided in this embodiment electrically connects the capacitor power supply circuit 2 and the capacitor module 3 as the backup power supply circuit, and connects the direct power supply circuit 1 to the backup power supply circuit through the dual-channel power supply selection circuit 4. When the direct power supply is lost, the backup power supply circuit works, improving the reliability of RTC power supply; in addition, the voltage reference chip used in the backup power supply circuit has the advantages of small volume, simple layout, and low price, which can effectively reduce costs.

[0046] The above-described embodiments merely represent several implementation manners of the present utility model, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several modifications and improvements can still be made, and these all belong to the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the appended claims.

Claims

1. A dual-channel backup circuit for RTC power supply, characterized in that Comprising: A direct power supply circuit, a capacitor power supply circuit, a capacitor module, and a dual-channel power supply selection circuit; A first input terminal of the dual-channel power supply selection circuit is electrically connected to the direct power supply circuit, a second input terminal of the dual-channel power supply selection circuit is electrically connected to an output terminal of the capacitor module, and an output terminal of the dual-channel power supply selection circuit is electrically connected to the RTC; An input terminal of the capacitor module is electrically connected to an output terminal of the capacitor power supply circuit.

2. The dual-path backup circuit according to claim 1, characterized in that, The direct power supply circuit includes: a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and an LDO chip; The LDO chip includes: a voltage input pin, a voltage output pin, and a ground pin; One end after the first capacitor and the second capacitor are connected in parallel is electrically connected to a +5V power supply voltage and the voltage input pin, and the other end is grounded; One end after the third capacitor and the fourth capacitor are connected in parallel is electrically connected to the voltage output pin and a first input terminal of the dual-channel power supply selection circuit, and the other end is grounded; The ground pin is grounded.

3. The dual-path standby circuit according to claim 1, wherein The capacitor power supply circuit includes: a triode, a first resistor, a second resistor, a third resistor, a fifth capacitor, a sixth capacitor, and a voltage reference chip; One end of the fifth capacitor and the sixth capacitor connected in parallel, one end of the first resistor, and the collector of the triode are all electrically connected to a +5V power supply voltage; The base of the triode is electrically connected to the other end of the first resistor and the cathode of the voltage reference chip, and the emitter of the triode is electrically connected to one end of the second resistor and serves as an output terminal of the capacitor power supply circuit; The reference pin of the voltage reference chip is electrically connected to the other end of the second resistor and one end of the third resistor; The other end of the fifth capacitor and the sixth capacitor connected in parallel, the anode of the voltage reference chip, and the other end of the third resistor are all grounded.

4. The dual-channel standby circuit according to any one of claims 1 to 3, characterized in that The dual-channel power supply selection circuit includes: a first diode and a second diode; The positive electrode of the first diode is a first input terminal of the dual-channel power supply selection circuit, the positive electrode of the second diode is a second input terminal of the dual-channel power supply selection circuit, and the negative electrode of the first diode and the negative electrode of the second diode are electrically connected and serve as an output terminal of the dual-channel power supply selection circuit.

5. The dual-path standby circuit according to claim 4, wherein, Further comprising: A filter circuit; An input terminal of the filter circuit is electrically connected to an output terminal of the dual-channel power supply selection circuit, and an output terminal of the filter circuit is electrically connected to the RTC.

6. The dual-path standby circuit according to claim 5, wherein, The filter circuit includes: a seventh capacitor and an eighth capacitor connected in parallel.

7. The dual-path standby circuit according to claim 6, wherein One end of the seventh capacitor is an input terminal of the filter circuit, one end of the eighth capacitor is an output terminal of the filter circuit, and the other end of the seventh capacitor and the other end of the eighth capacitor are electrically connected and grounded.

8. The dual-path standby circuit according to any one of claims 1 to 3, characterized in that The capacitor module includes: a ninth capacitor and a tenth capacitor connected in parallel.

9. The dual-path standby circuit according to claim 8, wherein Both the ninth capacitor and the tenth capacitor are lithium-ion capacitors; The positive electrode of the ninth capacitor C9 is an input terminal of the capacitor module, the positive electrode of the tenth capacitor is an output terminal of the capacitor module, and the negative electrode of the ninth capacitor and the negative electrode of the tenth capacitor are electrically connected and grounded.

10. The dual-path standby circuit according to any one of claims 1 to 3, characterized in that, The output terminal of the dual-channel power supply selection circuit outputs a 3.3V voltage.

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