Slow-start circuit suitable for power supply boost

Abstract

The present invention relates to a slow-start circuit suitable for boosting power supply. The circuit includes a load module, a control module, a ripple elimination module, a power module, a first switch module, and a second switch module. The power module is connected to the control module. The first switch module is arranged at the output end of the power module and is respectively connected to the load module and the ripple elimination module to form a boost power supply branch and an absorption branch. The first switch module is also connected to the control module to form a first switch branch. The first switch branch is activated at the initial stage of boosting power supply to synchronize the boost power supply branch and the absorption branch. The second switch module is respectively connected to the control module and the first switch module to form a second switch branch. The second switch branch is activated T time after the first switch branch is activated to cooperate with the first switch branch to jointly control the boost power supply of the power module, and the T time is not less than the charging time of the absorption branch. This circuit improves circuit stability.

Description

Technical Field

[0001] The present invention relates to the technical field of electric meters, and in particular to a slow-start circuit suitable for power supply boosting. Background Art

[0002] With the expansion of the market for smart terminals, such as prepaid electricity meters, the demand for CIUs is increasing. Boosting power supplies using batteries and other power sources is becoming increasingly common. To reduce back-end ripple, designers typically add electrolytic capacitors to the back end of the boost circuit. However, how to control the battery power supply to the boost circuit at specific times through chip control has become a must-consider for every designer.

[0003] Most existing solutions use two transistor conversion circuits to power the boost circuit. Because the electrolytic capacitor needs to be charged in the initial stage of the power boost, this results in excessive current in the initial stage of the transistor being turned on, and the voltage of the battery or other power supply is pulled too low, affecting the battery or other power supply to the MCU, causing frequent MCU resets and circuit instability. Summary of the Invention

[0004] In view of the above problems, an object of the present invention is to provide a slow-start circuit suitable for power boost supply, which can effectively improve circuit stability.

[0005] To achieve the above objectives, the technical solution of the present invention is: a slow-start circuit suitable for power supply boost, the circuit comprising a load module, a control module, a ripple elimination module, a power module, a first switch module and a second switch module, the power module being connected to the control module, characterized in that:

[0006] The first switch module is arranged at the output end of the power module and is respectively connected to the load module and the ripple elimination module to form a boost power supply branch and an absorption branch. The first switch module is also connected to the control module to form a first switch branch. The first switch branch is activated at the initial stage of boost power supply to synchronously turn on the boost power supply branch and the absorption branch.

[0007] The second switch module is respectively connected to the control module and the first switch module to form a second switch branch. The second switch branch is activated T time after the first switch branch is activated to cooperate with the first switch branch to jointly control the boost power supply of the power module. The T is not less than the charging time of the absorption branch.

[0008] Furthermore, the circuit further includes an interference removal module, one end of which is connected between the power module and the first switch module and the other end of which is connected between the control module of the first switch branch and the first switch module.

[0009] Furthermore, the circuit further includes an anti-reset module provided between the control module of the first switch branch and the first switch module to prevent the first switch module from operating during boost supply and pulling down the power module to a level that resets the control module;

[0010] The other end of the interference removal module is connected between the anti-reset module and the first switch module.

[0011] Furthermore, the first switch module and the second switch module are both triodes, wherein the first switch module is a PNP triode and the second switch module is an NPN triode.

[0012] Furthermore, the ripple elimination module includes an electrolytic capacitor with one end connected between the collector of the PNP transistor and the load module and the other end grounded.

[0013] Furthermore, the value of T is 150ms.

[0014] Furthermore, the interference removal module includes a first resistor.

[0015] Furthermore, the resistance of the first resistor is 100KΩ.

[0016] Furthermore, the anti-reset module includes a second resistor.

[0017] Furthermore, the resistance of the second resistor is 4.7KΩ.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] By adding a first switch branch in the circuit, in the initial stage of boost power supply, only the first switch branch is activated to enable the power module to power the load module and charge the ripple elimination module, and after an interval of time T, the second switch branch is opened to cooperate with the first switch branch to provide normal service for the boost power supply. This effectively solves the problem that when providing boost power, the charging current flowing through the ripple elimination module is too large, causing the power supply to be quickly pulled down, resulting in reset of the control module, flickering of the liquid crystal, and circuit instability in the previous circuit, greatly improving the overall stability of the circuit. In addition, the circuit structure is simple in design, highly portable, low in production cost, and widely applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural block diagram of a slow-start circuit suitable for power boost supply in this application.

[0021] Figure 2 This is a circuit schematic diagram of a slow-start circuit for power boost supply applicable to this application. DETAILED DESCRIPTION

[0022] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0023] Figure 1-2 A preferred embodiment of the present application is shown as a slow-start circuit suitable for power boost supply. As shown in the figure, the circuit includes a load module 1, a control module 2, a ripple elimination module 3, a power module 4, a first switch module 5 and a second switch module 6, and the power module 4 is connected to the control module 2.

[0024] As mentioned above, in the existing conversion circuit composed of two transistors, the charging current is too large in the initial stage of the circuit boost power supply, which can easily cause the power supply to be quickly pulled down, resulting in insufficient power supply and reset of the control module, affecting the circuit stability and overall performance.

[0025] To solve this problem, the present application sets the first switch module 5 at the output end of the power module 4, and connects it to the load module 1 and the ripple elimination module 3 respectively to form a boost power supply branch S and an absorption branch Q. The first switch module 5 is also connected to the control module 2 to form a first switch branch L1. The first switch branch L1 is activated at the initial stage of the boost power supply to synchronize the boost power supply branch S and the absorption branch Q. At the same time, the second switch module 6 is connected to the control module 2 and the first switch module 5 respectively to form a second switch branch L2. The second switch branch L2 is activated T time after the first switch branch L1 is activated to cooperate with the first switch branch L1 to jointly control the boost power supply of the power module 4. The T is not less than the charging time of the absorption branch Q.

[0026] In this way, by setting the first switch module at the output end of the power supply module, the first switch branch formed by it and the control module is activated at the initial stage of power supply, and the second switch branch formed by the second switch module, the first switch module and the control module is turned on after an interval of T time, and the charging time of the absorption branch is fully utilized, and it is used as the interval time for the action of the two switch branches, thereby effectively ensuring that only one switch component is activated in the initial stage of boost power supply, the charging current will not be too large, and the power supply voltage will not be pulled too low to reset the control module, thereby improving the circuit stability, and the cooperation of the two branches in the later stage effectively ensures that the circuit provides normal current and the power supply purpose is achieved, thereby improving the overall performance of the circuit.

[0027] To prevent interference from causing the first switch module to misconnect, the circuit of the present application further includes an interference removal module 7. One end of the interference removal module 7 is connected between the power module 4 and the first switch module 5, and the other end is connected between the control module 2 and the first switch module 5 forming the first switch branch L1. In this embodiment, the interference removal module 7 is a first resistor R100 for filtering out small signal interference. At the same time, in this embodiment, the resistance value of R100 is preferably 100KΩ.

[0028] In order to prevent the power supply voltage from being pulled too low when the first switch module is operated and causing the control module to reset, the circuit of the present application also includes an anti-reset module 8 arranged between the control module 2 and the first switch module 5 forming the first switch branch L1 to prevent the first switch module 5 from being operated during the boost supply and pulling the power module 4 down to a level that resets the control module 2. The other end of the interference module 7 is connected between the anti-reset module 8 and the first switch module 5.

[0029] In the present application, the first switch module 5 and the second switch module 6 are both triodes, wherein the first switch module 5 is a PNP type triode V102, and the second switch module 6 is an NPN type triode V101. Thus, in the initial stage of the circuit boost power supply, the first switch module 5 is actuated to turn on V102, and the conduction of V102 means that the current flowing through its base is very small, and as Figure 2 As shown, the base of V102 is connected to the control module. In order to prevent the power supply from being pulled too low due to the small base current on V102, causing the control module to be reset, the anti-reset module 8 is preferably composed of a second resistor R102. This not only ensures the realization of the anti-reset function, but also simplifies the circuit and reduces the cost.

[0030] In this circuit, the resistance of the second resistor R102 is preferably 4.7KΩ. Furthermore, the first and second switch modules may also be constructed using MOS transistors, or one may be constructed using a triode and the other using a MOS transistor. The specific combination is selected based on actual needs. Regardless of the switch device selected, as long as the objectives of this application can be achieved, it falls within the scope of protection of this application.

[0031] The ripple elimination module 3 in this application includes an electrolytic capacitor CE100, one end of which is connected between the collector of the PNP transistor V102 and the load module 1, and the other end is grounded. Based on its charge and discharge characteristics, this application preferably selects T as 150ms. That is, after the first switch branch is turned on for 150ms, the second switch branch is turned on to cooperate with the first switch branch to ensure the boosted power supply.

[0032] The following text Figure 2 Briefly describe the working process:

[0033] VBAT is the power module 1, which is preferably a battery here. VBAT_3V is the input voltage of the back-end boost circuit. GND is the ground of the control module 2. IO1 and IO2 are common IO ports of the control module 2.

[0034] During normal operation, IO1 is set to output low, IO2 is set to output high or input is disabled, at this time V101 and V102 are all turned off.

[0035] When it is necessary to boost the voltage and supply power to the back-end load module 1, IO1 is set to output low first and V102 is turned on. At this time, the battery charges the back-end capacitor CE100 through V102. Since the base current is controllable and only one transistor is turned on, the charging current will not be too large. After T = 150ms, IO1 is set to high again. At this time, V101 and V102 are all turned on. Since the back-end CE100 is fully charged, the current of V102 is controllable at this time, and the VBAT voltage will not be pulled too low due to excessive current.

[0036] Therefore, by configuring the first switch branch in the circuit, in the initial stage of the boost power supply, only the first switch branch is activated so that the power module can supply power to the load module and charge the ripple elimination module, and after an interval of time T, the second switch branch is opened to cooperate with the first switch branch to provide normal service for the boost power supply. This effectively solves the problem that in the previous circuit, when providing boost power, the charging current flowing through the ripple elimination module is too large, causing the power supply to be quickly pulled down, resulting in the reset of the control module, flickering of the liquid crystal, and circuit instability. It has a good effect of slowly increasing the boost power supply current, greatly improving the overall stability of the circuit. In addition, the circuit structure is simple in design, highly portable, low in production cost, and widely applicable.

[0037] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A slow-start circuit suitable for power supply boosting, the circuit comprising a load module (1), a control module (2), a ripple elimination module (3), a power module (4), a first switch module (5) and a second switch module (6), wherein the power module (4) is connected to the control module (2), and is characterized in that: The first switch module (5) is arranged at the output end of the power module (4) and is respectively connected to the load module (1) and the ripple elimination module (3) to form a boost power supply branch (S) and an absorption branch (Q). The first switch module (5) is also connected to the control module (2) to form a first switch branch (L1). The first switch branch (L1) is activated at the initial stage of boost power supply to enable the boost power supply branch (S) and the absorption branch (Q) to be synchronously turned on. The second switch module (6) is respectively connected to the control module (2) and the first switch module (5) to form a second switch branch (L2). The second switch branch (L2) is activated T time after the first switch branch (L1) is activated to cooperate with the first switch branch (L1) to jointly control the boost power supply of the power module (4), wherein T is not less than the charging time of the absorption branch (Q).

2. The slow-start circuit according to claim 1, wherein: The circuit further comprises an interference removal module (7), one end of the interference removal module (7) being connected between the power supply module (4) and the first switch module (5) and the other end being connected between the control module (2) of the first switch branch (L1) and the first switch module (5).

3. The slow-start circuit according to claim 2, wherein: The circuit further comprises an anti-reset module (8) arranged between the control module (2) of the first switch branch (L1) and the first switch module (5) to prevent the first switch module (5) from operating during boost supply and pulling down the power module (4) to a level that resets the control module (2); The other end of the interference removal module (7) is connected between the anti-reset module (8) and the first switch module (5).

4. The slow-start circuit according to claim 3, wherein: The first switch module (5) and the second switch module (6) are both triodes, wherein the first switch module (5) is a PNP-type triode (V102) and the second switch module (6) is an NPN-type triode (V101).

5. The slow-start circuit according to claim 4, characterized in that: The ripple elimination module (3) comprises an electrolytic capacitor (CE100) having one end connected between the collector of the PNP transistor (V102) and the load module (1) and the other end grounded.

6. The slow-start circuit according to claim 1, wherein: The value of T is 150ms.

7. The slow-start circuit according to claim 2, wherein: The interference removal module (7) comprises a first resistor (R100).

8. The slow-start circuit according to claim 7, characterized in that: The resistance of the first resistor (R100) is 100KΩ.

9. The slow-start circuit according to claim 3, characterized in that: The anti-reset module (8) includes a second resistor (R102).

10. The slow-start circuit according to claim 9, characterized in that: The resistance of the second resistor (R102) is 4.7KΩ.

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