Circuit for realizing low-power-consumption wake-up by using RX pin of CAN (Controller Area Network) interface chip

Abstract

The utility model discloses a circuit for realizing low-power-consumption wake-up by using an RX pin of a CAN (Controller Area Network) interface chip. The circuit is characterized in that the output end of a power supply is connected with one input end of an MCU (Microprogrammed Control Unit), the RX pin of the CAN interface chip is connected with the other input end of the MCU, the input end of an inverting circuit module is connected with the RX pin of the CAN interface chip, and the output port of the inverting circuit module is connected with the input end of the power supply; the inverting circuit module comprises a triode Q1, a resistor R3, a resistor R4 and a resistor R5, an emitter and a base of the triode Q1 are connected through the resistor R4, the base of the triode Q1 is connected with an RX pin of the CAN interface chip through the resistor R5, a collector of the triode Q1 is grounded after being connected with the resistor R3, a first node is arranged on a connecting line of the collector of the triode Q1 and the resistor R3, and a second node is arranged on the connecting line of the collector of the triode Q1 and the resistor R3. And a branch is led out from the first node and is connected with the power supply module. Through the wake-up circuit provided by the invention, the risk of power supply feed of the vehicle-mounted equipment is greatly reduced.

Description

Technical Field

[0001] The present application relates to the technical field of wake-up circuits for vehicle-mounted equipment, and in particular to a low-power wake-up circuit. Background Art

[0002] With the development of automotive electronics, there are more and more types of on-board electrical appliances in each car. These electronic devices must enter sleep or shutdown mode after the car is turned off. Otherwise, if there is no ignition for a long time to charge the battery, the battery will be drained and need to be jumpered to start again.

[0003] In order to enable electronic devices to have sleep / wake-up functions, such as Figure 1 As shown, in the prior art, the CAN remote wake-up method in the vehicle-mounted device is that after the CAN interface chip receives the wake-up signal, the RX pin of the CAN interface chip of the vehicle-mounted device is set to a low level, and the MCU detects the RX level to wake up the device. After the device detects that there is no wake-up signal, the device enters a dormant state, and the RX pin of the CAN interface chip is a high level; when the CAN interface chip detects the wake-up signal, the RX pin of the CAN interface chip is a low level to wake up the device and enter a normal working mode. However, in this dormant mode, when the system is in dormant state, the power supply needs to continue to output power to the MCU. The MCU monitors the RX pin of the CAN interface chip and wakes up the device when there is a wake-up signal from the CAN. However, when the device is dormant, the power supply needs to continue to output power to the MCU, and the dormant current will be relatively high, increasing the risk of power failure of the vehicle-mounted device power supply. Utility Model Content

[0004] Based on this, in response to the above technical problems, a low-power wake-up circuit is provided using the RX pin of a CAN interface chip to solve the problem that the existing technology requires continuous power supply to the MCU to receive the wake-up signal when using the vehicle-mounted device power supply, and there is a high risk of power feeding of the vehicle-mounted device power supply.

[0005] A low-power wake-up circuit using the RX pin of a CAN interface chip, the circuit comprising: a power module of an on-board device, an MCU module, a CAN interface chip module, and an inverting circuit module;

[0006] The output end of the power supply is connected to an input end of the MCU, the RX pin of the CAN interface chip is connected to another input end of the MCU, the input end of the inverter circuit module is connected to the RX pin of the CAN interface chip, and the output port of the inverter circuit module is connected to the input end of the power supply;

[0007] The inverting circuit module includes a transistor Q1, resistors R3, R4 and a resistor R5. The emitter set and the base set of the transistor Q1 are connected via the resistor R4. The base set of the transistor Q1 is connected to the RX pin of the CAN interface chip via the resistor R5. The collector of the transistor Q1 is connected to the resistor R3 and then to the ground. A first node is set on the connecting line between the collector of the transistor Q1 and the resistor R3, and a branch is led out from the first node to connect the power supply module.

[0008] In the above scheme, optionally, the CAN interface chip module includes: a CAN interface chip U1, an inductor L3, a resistor R1, a resistor R2, capacitors C1, C2, C3, C4, C5, C6, C7, inductors L1 and L2, and a bidirectional TVS tube D1;

[0009] The VCC interface of the CAN interface chip U1 is connected to the inductor L2, a second node and a third node are set at the connection between the VCC interface of the CAN interface chip U1 and the inductor L2, and a branch is led out from the second node and the third node to be connected to the capacitors C3 and C4 respectively and then grounded;

[0010] The VIO interface of the CAN interface chip U1 is connected to the inductor L1, and a fourth node and a fifth node are provided at the connection between the VIO interface of the CAN interface chip U1 and the inductor L1, and a branch is led out from the fourth node and the fifth node, respectively connected to the capacitors C1 and C2, and then grounded;

[0011] The CANH1 interface and the CANL1 interface of the CAN interface chip U1 are respectively connected to one end of the inductor L3, the other end of the inductor L3 is connected to the receiving port of the CAN signal, and the sixth node, the seventh node, the eighth node, the ninth node, the tenth node, and the eleventh node are set on the other end of the inductor L3 and the receiving port of the CAN signal; a branch is respectively led out from the sixth node and the seventh node and connected to one end of the resistor R1 and the resistor R2 respectively, and the other end of the resistor R1 and the resistor R2 is connected to one end of the capacitor C7 and then grounded; a branch is respectively led out from the eighth node and the ninth node and connected to the capacitor C5 and the capacitor C6 respectively and then grounded, and a branch is respectively led out from the tenth node and the eleventh node and connected to the bidirectional TVS tube D1 and then grounded.

[0012] In the above solution, optionally, the emitter of the transistor Q1 is externally connected to a 3.3V power supply.

[0013] In the above solution, optionally, the resistance of the resistor R3 is 10KΩ.

[0014] In the above solution, optionally, the transistor Q1 adopts the MMUN2114LT1G model.

[0015] This application has at least the following beneficial effects:

[0016] This application connects an inverting circuit module to the RX pin of the CAN interface chip, inverts the RX pin level of the CAN interface chip, and outputs it to the enable pin of the power supply to control the power output. After the device enters sleep mode, the power supply stops outputting, and the enable pin of the power supply monitors the RX pin of the CAN interface chip through the inverting circuit; the RX pin is at a high level after the CAN interface chip goes into sleep mode, and outputs a low level to the power enable pin through the inverting circuit, and the power output is turned off; when the CAN interface chip detects a wake-up signal, the RX pin is at a low level, and outputs a high level to the power enable pin through the inverting circuit, and the high level of the power enable pin controls the power output to power on the device, and the wake-up device starts working. As a result, when the device is in sleep mode, the MCU of the vehicle-mounted device does not need to be powered at all times, that is, the power supply does not need to supply power to the MCU at all times, reducing the risk of power feeding of the vehicle-mounted device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The framework diagram of the wake-up circuit of the vehicle-mounted device in the prior art;

[0018] Figure 2 A framework diagram of a low-power wake-up circuit using the RX pin of a CAN interface chip provided in one embodiment of the present application;

[0019] Figure 3 This is a detailed circuit schematic diagram of an inverter circuit module and a CAN interface chip module provided in one embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] In one embodiment, Figure 2 As shown, a low-power wake-up circuit using the RX pin of a CAN interface chip is provided, the circuit comprising: a power module of an on-board device, an MCU module, a CAN interface chip module, and an inverting circuit module;

[0022] The output end of the power supply is connected to an input end of the MCU, the RX pin of the CAN interface chip is connected to another input end of the MCU, the input end of the inverter circuit module is connected to the RX pin of the CAN interface chip, and the output port of the inverter circuit module is connected to the input end of the power supply;

[0023] The inverting circuit module includes a transistor Q1, resistors R3, R4 and a resistor R5. The emitter set and the base set of the transistor Q1 are connected via the resistor R4. The base set of the transistor Q1 is connected to the RX pin of the CAN interface chip via the resistor R5. The collector of the transistor Q1 is connected to the resistor R3 and then to the ground. A first node is set on the connecting line between the collector of the transistor Q1 and the resistor R3, and a branch is led out from the first node to connect the power supply module.

[0024] Specifically, Figure 3 As shown, U1's 4 (RXD1) pin is high when no wake-up is detected after the device goes into sleep mode. When CAN1-H and CAN1-L detect the wake-up signal, U1's 4 (RXD1) pin becomes low. At this time, RXD1 controls Q1 to turn on, and CAN1_INH is high to activate the device power supply, so that the device starts to work normally. When the system enters sleep mode, RXD1 becomes high, U1's 4 (RXD1) pin Q1 is turned off, and CAN1_INH is low to turn off the device power supply, so that the device enters sleep mode.

[0025] In the above-mentioned low-power wake-up circuit using the RX pin of the CAN interface chip, an inverting circuit module is connected to the RX pin of the CAN interface chip to invert the RX pin level of the CAN interface chip and output it to the enable pin of the power supply to control the power output. After the device enters sleep mode, the power supply stops outputting, and the enable pin of the power supply monitors the RX pin of the CAN interface chip through the inverting circuit; the RX pin is at a high level after the CAN interface chip goes into sleep mode, and outputs a low level to the power enable pin through the inverting circuit, and the power output is turned off; when the CAN interface chip detects a wake-up signal, the RX pin is at a low level, and outputs a high level to the power enable pin through the inverting circuit, and the high level of the power enable pin controls the power output to power on the device, and the wake-up device starts working. As a result, when the device is in sleep mode, the MCU of the vehicle-mounted device does not need to be powered at all times, that is, the power supply does not need to supply power to the MCU at all times, reducing the risk of power feeding of the vehicle-mounted device.

[0026] In one embodiment, Figure 3 As shown, the CAN interface chip module includes: a CAN interface chip U1, an inductor L3, a resistor R1, a resistor R2, capacitors C1, C2, C3, C4, C5, C6, C7, inductors L1 and L2, and a bidirectional TVS tube D1;

[0027] The VCC interface of the CAN interface chip U1 is connected to the inductor L2, a second node and a third node are set at the connection between the VCC interface of the CAN interface chip U1 and the inductor L2, and a branch is led out from the second node and the third node to be connected to the capacitors C3 and C4 respectively and then grounded;

[0028] The VIO interface of the CAN interface chip U1 is connected to the inductor L1, and a fourth node and a fifth node are provided at the connection between the VIO interface of the CAN interface chip U1 and the inductor L1, and a branch is led out from the fourth node and the fifth node, respectively connected to the capacitors C1 and C2, and then grounded;

[0029] The CANH1 interface and the CANL1 interface of the CAN interface chip U1 are respectively connected to one end of the inductor L3, the other end of the inductor L3 is connected to the receiving port of the CAN signal, and the sixth node, the seventh node, the eighth node, the ninth node, the tenth node, and the eleventh node are set on the other end of the inductor L3 and the receiving port of the CAN signal; a branch is respectively led out from the sixth node and the seventh node and connected to one end of the resistor R1 and the resistor R2 respectively, and the other end of the resistor R1 and the resistor R2 is connected to one end of the capacitor C7 and then grounded; a branch is respectively led out from the eighth node and the ninth node and connected to the capacitor C5 and the capacitor C6 respectively and then grounded, and a branch is respectively led out from the tenth node and the eleventh node and connected to the bidirectional TVS tube D1 and then grounded.

[0030] In one embodiment, the emitter of the transistor Q1 is externally connected to a 3.3V power supply.

[0031] In one embodiment, the resistance of the resistor R3 is 10KΩ.

[0032] In one embodiment, the transistor Q1 is of model MMUN2114LT1G.

[0033] In the prior art, when the device is dormant, the MCU power supply needs to be maintained, and the RX pin of the CAN interface chip needs to be used to wake up the device. The utility model can realize that when the device is dormant, the MCU power supply can be turned off, and the device can be woken up by using the RX pin of the CAN interface chip.

[0034] The device sleep current of the prior art is relatively large; the utility model can turn off the MCU power supply when the device is in sleep mode, reduce the device sleep current, improve the battery life, and reduce the risk of battery power feeding.

[0035] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0036] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A low-power wake-up circuit using the RX pin of a CAN interface chip, characterized in that: The circuit includes: a power module of the vehicle-mounted equipment, an MCU module, a CAN interface chip module and an inverter circuit module; The output end of the power supply is connected to an input end of the MCU, the RX pin of the CAN interface chip is connected to another input end of the MCU, the input end of the inverter circuit module is connected to the RX pin of the CAN interface chip, and the output port of the inverter circuit module is connected to the input end of the power supply; The inverting circuit module includes a transistor Q1, resistors R3, R4 and a resistor R5. The emitter set and the base set of the transistor Q1 are connected via the resistor R4. The base set of the transistor Q1 is connected to the RX pin of the CAN interface chip via the resistor R5. The collector of the transistor Q1 is connected to the resistor R3 and then to the ground. A first node is set on the connecting line between the collector of the transistor Q1 and the resistor R3, and a branch is led out from the first node to connect the power supply module.

2. The low-power wake-up circuit using the CAN interface chip RX pin according to claim 1, characterized in that: The CAN interface chip module includes: a CAN interface chip U1, an inductor L3, a resistor R1, a resistor R2, capacitors C1, C2, C3, C4, C5, C6, C7, inductors L1 and L2, and a bidirectional TVS tube D1; The VCC interface of the CAN interface chip U1 is connected to the inductor L2, a second node and a third node are set at the connection between the VCC interface of the CAN interface chip U1 and the inductor L2, and a branch is led out from the second node and the third node to be connected to the capacitors C3 and C4 respectively and then grounded; The VIO interface of the CAN interface chip U1 is connected to the inductor L1, and a fourth node and a fifth node are provided at the connection between the VIO interface of the CAN interface chip U1 and the inductor L1, and a branch is led out from the fourth node and the fifth node, respectively connected to the capacitors C1 and C2, and then grounded; The CANH1 interface and the CANL1 interface of the CAN interface chip U1 are respectively connected to one end of the inductor L3, the other end of the inductor L3 is connected to the receiving port of the CAN signal, and the sixth node, the seventh node, the eighth node, the ninth node, the tenth node, and the eleventh node are set on the other end of the inductor L3 and the receiving port of the CAN signal; a branch is respectively led out from the sixth node and the seventh node and connected to one end of the resistor R1 and the resistor R2 respectively, and the other end of the resistor R1 and the resistor R2 is connected to one end of the capacitor C7 and then grounded; a branch is respectively led out from the eighth node and the ninth node and connected to the capacitor C5 and the capacitor C6 respectively and then grounded, and a branch is respectively led out from the tenth node and the eleventh node and connected to the bidirectional TVS tube D1 and then grounded.

3. The low-power wake-up circuit using the CAN interface chip RX pin according to claim 1, characterized in that: The emitter of the transistor Q1 is externally connected to a 3.3V power supply.

4. The low-power wake-up circuit using the CAN interface chip RX pin according to claim 1, characterized in that: The resistance value of the resistor R3 is 10KΩ.

5. The low-power wake-up circuit using the CAN interface chip RX pin according to claim 1, characterized in that: The transistor Q1 is of model MMUN2114LT1G.

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