Watchdog control circuit and charging management terminal

Abstract

The utility model discloses a watchdog control circuit and a charging management terminal, a pin 1 of a watchdog chip U4 is connected with a VCC through a resistor R34, a pin 2 of the watchdog chip U4 is grounded, two ends of a capacitor C5 are respectively connected with the pin 1 and the pin 2 of the watchdog chip U4, a pin 3 of the watchdog chip U4 is grounded through a resistor R1, two ends of a power-on switch S2 are respectively connected with the VCC and the pin 3 of the watchdog chip U4, and two ends of the power-on switch S2 are respectively connected with the VCC and the pin 3 of the watchdog chip U4. A pin 4 of the watchdog chip U4 is connected with the VCC through a resistor R46 and a resistor R11 in sequence, a pin 5 of the watchdog chip U4 is connected to one end of a resistor R41, and a pin 6 of the watchdog chip U4 is connected to the VCC through a resistor R213; the watchdog control circuit further comprises a short circuit sub-circuit, and the pin 1 of the watchdog chip U4 is operably grounded through the short circuit sub-circuit. According to the watchdog control circuit and the charging management terminal provided by the utility model, the timing work of the watchdog circuit is paused in the programming process of the main control chip, so that the timing period cannot be reached, and a low-level reset signal is not sent.

Description

Technical Field

[0001] The utility model relates to a watchdog control circuit and a charging management terminal. Background Art

[0002] DIN-rail intelligent charging management terminals are complex and require an operating system. To ensure product reliability and self-recovery, an external watchdog circuit is typically added. This circuit is fed by the main chip to maintain normal operation and a high reset signal.

[0003] The watchdog timer typically lasts less than 1 minute. However, chips with operating systems require programming kernel drivers and application-layer programs, a process that takes a long time, typically 2 to 3 minutes. The watchdog timer begins timing after power is applied. If the program is not programmed by the end of a cycle, the system cannot provide a feed signal, so the watchdog outputs a reset signal, causing programming failure. Utility Model Content

[0004] The utility model provides a watchdog control circuit and a charging management terminal to solve the above-mentioned technical problems, specifically adopting the following technical solutions:

[0005] A watchdog control circuit, comprising: a watchdog chip U4, a resistor R34, a capacitor C5, a resistor R1, a power-on switch S2, a resistor R213, a resistor R41, a resistor R46 and a resistor R11;

[0006] Pin 1 of the watchdog chip U4 is connected to VCC through the resistor R34, pin 2 of the watchdog chip U4 is grounded, two ends of the capacitor C5 are respectively connected to pin 1 and pin 2 of the watchdog chip U4, pin 3 of the watchdog chip U4 is grounded through the resistor R1, two ends of the power-on switch S2 are respectively connected to VCC and pin 3 of the watchdog chip U4, pin 4 of the watchdog chip U4 is sequentially connected to VCC through the resistor R46 and the resistor R11, pin 5 of the watchdog chip U4 is connected to one end of the resistor R41, and pin 6 of the watchdog chip U4 is connected to VCC through the resistor R213;

[0007] The watchdog control circuit further includes a shorting subcircuit, which is operable to ground pin 1 of the watchdog chip U4.

[0008] Furthermore, the shorting sub-circuit includes a shorting switch S3, a port 1 of the shorting switch S3 is grounded, and a port 2 of the shorting switch S3 is connected to pin 1 of the watchdog chip U4.

[0009] Furthermore, the short-circuit sub-circuit includes a relay, two ends of the relay are respectively connected to the ground and the pin 1 of the watchdog chip U4, and the control end of the relay is connected to an external signal control device.

[0010] Furthermore, the relay is a photorelay.

[0011] Furthermore, the resistance range of the resistor R1 is 500Ω to 180KΩ.

[0012] Furthermore, the watchdog chip U4 is SGM821.

[0013] Furthermore, VCC is 3.3V.

[0014] A guide rail type intelligent charging management terminal includes a main control chip and the aforementioned watchdog control circuit, wherein the watchdog control circuit is connected to the main control chip.

[0015] The utility model is beneficial in that the watchdog control circuit and charging management terminal provided by the utility model suspend the timing of the watchdog circuit during the programming process of the main control chip, so that the timing cycle cannot be reached and a low-level reset signal is not sent. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 The utility model is a schematic diagram of a watchdog control circuit. DETAILED DESCRIPTION

[0018] The following describes in detail embodiments of the present application. 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 to be used to explain the present application, and should not be construed as limiting the present application.

[0019] This application discloses a watchdog control circuit for use in a DIN-rail intelligent charging management terminal for managing electric vehicle charging. The DIN-rail intelligent charging management terminal includes a main control chip and a watchdog control circuit connected to the main control chip. The watchdog circuit is connected to the main control chip via a feed signal (RUN) and a reset signal (RST).

[0020] The rail-mounted intelligent charging management terminal has complex functions and requires high real-time performance, requiring an operating system solution. The main control chip with the operating system requires the kernel driver and application layer programs to be burned, which is a time-consuming process. The watchdog control circuit of this application can still operate normally during the main control chip burning process without sending a low-level reset signal.

[0021] like Figure 1 As shown, the watchdog control circuit disclosed in the present application includes: a watchdog chip U4, a resistor R34, a capacitor C5, a resistor R1, a power-on switch S2, a resistor R213, a resistor R41, a resistor R46 and a resistor R11.

[0022] Specifically, pin 1 of the watchdog chip U4 is connected to VCC via a resistor R34. In this application, VCC is 3.3 V. In this application, the watchdog chip U4 is SGM821.

[0023] Pin 2 of watchdog chip U4 is grounded, and the terminals of capacitor C5 are connected to pins 1 and 2 of watchdog chip U4, respectively. Pin 3 of watchdog chip U4 is grounded via resistor R1, which has a resistance range of 500Ω to 180kΩ. Power-on switch S2 is connected to VCC and pin 3 of watchdog chip U4, respectively. Pin 4 of watchdog chip U4 is connected to VCC via resistors R46 and R11, respectively. Pin 5 of watchdog chip U4 is connected to one end of resistor R41, and pin 6 of watchdog chip U4 is connected to VCC via resistor R213.

[0024] In this application, the main control chip is connected to pins 4, 5, and 6 of the watchdog chip U4. The main control chip sends a dog feeding signal to pin 4 of the watchdog chip U4, and pin 6 of the watchdog chip U4 transmits a high level to the main control chip.

[0025] The watchdog control circuit further includes a shorting subcircuit operable to connect pin 1 of the watchdog chip U4 to ground.

[0026] In an embodiment of the present application, the short-circuit sub-circuit includes a short-circuit switch S3, port 1 of the short-circuit switch S3 is grounded, and port 2 of the short-circuit switch S3 is connected to pin 1 of the watchdog chip U4. In this way, when the program needs to be burned, S3 is short-circuited so that the power input pin (pin 1) of the watchdog chip U4 is directly grounded, and energy is consumed between 3.3V and GND through R34. The reset pin 6 is an open-drain output, and there is a pull-up resistor on the periphery, and the reset signal is always high. The watchdog circuit is not allowed to work, that is, the watchdog does not count, the timing cycle cannot be reached, and the reset signal is not output. In this way, even if the main control chip cannot send a dog feeding signal to the watchdog chip U4 during the burning period, the watchdog circuit will not send a low-level reset signal.

[0027] As another optional embodiment, the shorting subcircuit includes a relay, with its two terminals connected to ground and pin 1 of the watchdog chip U4, respectively. The relay's control terminal is connected to an external signal control device. Preferably, the relay is a photorelay. The photorelay can change its on / off state upon receiving an external control signal. Therefore, during chip programming, a control signal can be sent to the photorelay via the external signal control device, switching the photorelay on and off, thereby controlling the on / off state of the shorting subcircuit.

[0028] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. A watchdog control circuit, characterized in that: Includes: watchdog chip U4, resistor R34, capacitor C5, resistor R1, power-on switch S2, resistor R213, resistor R41, resistor R46 and resistor R11; Pin 1 of the watchdog chip U4 is connected to VCC through the resistor R34, pin 2 of the watchdog chip U4 is grounded, two ends of the capacitor C5 are respectively connected to pin 1 and pin 2 of the watchdog chip U4, pin 3 of the watchdog chip U4 is grounded through the resistor R1, two ends of the power-on switch S2 are respectively connected to VCC and pin 3 of the watchdog chip U4, pin 4 of the watchdog chip U4 is sequentially connected to VCC through the resistor R46 and the resistor R11, pin 5 of the watchdog chip U4 is connected to one end of the resistor R41, and pin 6 of the watchdog chip U4 is connected to VCC through the resistor R213; The watchdog control circuit further includes a shorting subcircuit, which is operable to ground pin 1 of the watchdog chip U4.

2. The watchdog control circuit according to claim 1, wherein: The shorting sub-circuit includes a shorting switch S3 , wherein port 1 of the shorting switch S3 is grounded, and port 2 of the shorting switch S3 is connected to pin 1 of the watchdog chip U4 .

3. The watchdog control circuit according to claim 1, wherein: The short-circuit subcircuit includes a relay, two ends of the relay are respectively connected to the ground and the pin 1 of the watchdog chip U4, and the control end of the relay is connected to an external signal control device.

4. The watchdog control circuit according to claim 3, wherein: The relay is a photorelay.

5. The watchdog control circuit according to claim 1, wherein: The resistance of the resistor R1 ranges from 500Ω to 180KΩ.

6. The watchdog control circuit according to claim 1, wherein: The watchdog chip U4 is SGM821.

7. The watchdog control circuit according to claim 1, wherein: VCC is 3.3V.

8. A charging management terminal, comprising a main control chip, characterized in that: It also includes a watchdog control circuit as described in any one of claims 1-7, and the watchdog control circuit is connected to the main control chip.

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