Transportation mode power-saving circuit

Abstract

The invention discloses a transportation mode power-saving circuit, which realizes disconnection and conduction from a battery to a working voltage circuit and leakage current test through two load switch circuits and a plurality of MOS (Metal Oxide Semiconductor) tube switch circuits. A slot and a physical switch do not need to be reserved on the appearance of a product, the attractiveness of the appearance of the product and the reliability of repeated switching of transportation modes are guaranteed, meanwhile, leakage current of a non-detachable product can be checked, and the quality of low power consumption of the product is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of power management, and in particular to a transport mode power saving circuit. Background Art

[0002] For products powered by lithium batteries and not removable, in order to ensure the service life of the lithium batteries, it is usually necessary to disconnect the battery from the circuit board before the product reaches the consumer, which is called the transportation mode. There are two main methods to achieve the transportation mode in the prior art. One is to use an insulating sheet to cut off the connection between the battery and the circuit board through physical insulation; the other is to use a physical switch to physically disconnect the power by flipping the switch.

[0003] For the technology using insulating sheets, it is necessary to design several metal springs on the circuit board, and then design a plug-in slot on the product housing. This technology has the following obvious problems:

[0004] Question 1: It is necessary to design a metal spring on the circuit board. The contact impedance of the spring may change due to metal oxidation, thus affecting the load capacity of the circuit.

[0005] Problem 2: It is difficult to reinsert the insulation sheet after it is pulled out, or the insulation sheet is easily lost and cannot be insulated again after passing electricity once.

[0006] Question 3: Since the insulating sheet needs to be plugged in and out, grooves need to be cut on the product casing, which affects the appearance.

[0007] The technology of using a physical switch to physically cut off the power supply by flipping the switch is relatively simple, but it also has the following obvious problems:

[0008] Question 1: Since a physical switch is used, a switch must be designed on the casing, which is very unfavorable for the product appearance design.

[0009] Question 2: Due to the use of physical switches, physical contact problems will inevitably occur, that is, there is a probability of poor contact or smooth switching.

[0010] Question 3: When the physical switch is disconnected, the circuit can prevent leakage. However, when the physical switch is closed, it is impossible to detect whether there is a large current leakage in the circuit.

[0011] Therefore, a shipping mode power saving circuit is needed to solve the above problems in the prior art. Summary of the invention

[0012] In order to solve the problems in the prior art, the present invention proposes a power saving circuit, which can realize static current testing through a USB interface, automatically connect the power output through the USB interface, realize automatic exit from the shipping mode, and disconnect the power output through a software logic control circuit to realize automatic entry into the shipping mode. The present invention is implemented by the following scheme:

[0013] A transport mode node circuit includes: a first power management chip U1, a second power management chip U2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first resistor R1, a second resistor R2 and a third resistor R3; wherein the input pin of the first power management chip U1 is connected to the output of the battery, the output pin of U1 is connected to the input pin of the second power management chip U2, and the output pin of U2 serves as the output of the power saving circuit; the gate of the first switch tube Q1 is connected to the first control terminal, the source of Q1 is grounded, and Q1 The drain of Q1 is connected to the gate of the second switch tube Q2, and the first resistor R1 is also connected between the gate and source of Q1; the gate of Q2 is also connected to the output of the battery through the third resistor R3, the source of Q2 is connected to the output of the battery, and the drain of Q2 is connected to the drain of the third switch tube Q3; the gate of Q3 is grounded, and the drain of Q3 is respectively connected to the enable pins of U1 and U2; the gate of the fourth switch tube Q4 is connected to the second control end, the source of Q4 is grounded, the drain of Q4 is connected to one end of the second resistor R2, and the other end of R2 is connected to the output end of U1.

[0014] As a further improvement of the present invention, the output of the power saving circuit provides an operating voltage VCC for the product.

[0015] As a further improvement of the present invention, the first switch tube and the fourth switch tube are NMOS tubes, and the second switch tube and the third switch tube are PMOS tubes.

[0016] As a further improvement of the present invention, the first control end inputs a first control signal, and the first control signal is a 5V voltage provided when the USB cable is inserted into the USB interface.

[0017] As a further improvement of the present invention, when the first control signal is input to the first control terminal, the first switch tube Q1 is turned on, thereby turning on the second switch tube Q2 and the third switch tube Q3, and the enable pins of the first power control chip U1 and the second power control chip U2 are pulled to a high level. At this time, the output pins of U1 and U2 can output normally, that is, the circuit conduction from the battery to the working voltage is realized; at this time, even if the input of the first control signal stops, the output pin of U1 continues to provide a high level for the enable pins of U1 and U2 through the second resistor R2, so that U1 and U2 are continuously turned on.

[0018] As a further improvement of the present invention, the second control terminal inputs a second control signal, and the second control signal is a high level signal.

[0019] As a further improvement of the present invention, the second control signal input by the second control terminal is triggered by at least one of the following operations: long pressing a single key, long pressing a combination of keys, and the communication terminal sending a control instruction.

[0020] As a further improvement of the present invention, when the second control terminal inputs the second control signal, the fourth switch tube Q4 is turned on, and the enable pins of the first power control chip U1 and the second power control chip U2 are pulled down to GND. At this time, U1 and U1 stop outputting, realizing the circuit disconnection from the battery to the working voltage.

[0021] As a further improvement of the present invention, when it is necessary to measure the leakage current of the internal circuit from the USB interface, first the second control terminal outputs a high level, turning on the fourth switch tube Q4, so that U1 and U2 disconnect the output; then plug in a customized USB cable without 5V voltage, connect the D+ of the external USB cable to VCC, and the D- to VBAT, connect the ammeter in series between D+ and D-, and test the leakage current of the internal circuit.

[0022] The beneficial effects of the present invention are as follows: the present invention realizes the disconnection and conduction of the battery to the working voltage circuit and the leakage current test through two load switch circuits and a plurality of MOS tube switch circuits. No slots and physical switches are required to be reserved in the product appearance, which ensures the aesthetic appearance of the product and the reliability of repeated switching of the transportation mode. At the same time, the leakage current of the non-detachable product can be checked, which ensures the low power consumption quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of a power-saving circuit of the present invention;

[0024] Figure 2 A circuit diagram of a power saving circuit of the present invention;

[0025] Figure 3 The present invention is a circuit diagram for testing static current of the USB interface circuit. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0027] The power saving circuit of the present invention has the following functions:

[0028] Function 1: Realize the power saving function in the transport mode, that is, the power supply can be disconnected through the circuit.

[0029] Function 2: Realize static current measurement of the subsequent circuit through the USB line to ensure the ultra-low power consumption performance of the product and prevent products with large leakage from entering the market.

[0030] Function 3: Automatically exit shipping mode through USB charging circuit and automatically enter shipping mode through software logic.

[0031] like Figure 1 As shown, the transport mode node circuit of the present invention includes: a first power management chip U1, a second power management chip U2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first resistor R1, a second resistor R2 and a third resistor R3.

[0032] Among them, the input pin of the first power management chip U1 is connected to the output of the battery, the output pin of U1 is connected to the input pin of the second power management chip U2, and the output pin of U2 serves as the output of the power saving circuit. The gate of the first switch tube Q1 is connected to the first control terminal, the source of Q1 is grounded, the drain of Q1 is connected to the gate of the second switch tube Q2, and the first resistor R1 is also connected between the gate and source of Q1. The gate of Q2 is also connected to the output of the battery through the third resistor R3, the source of Q2 is connected to the output of the battery, and the drain of Q2 is connected to the drain of the third switch tube Q3. The gate of Q3 is grounded, and the drain of Q3 is connected to the enable pins of U1 and U2 respectively. The gate of the fourth switch tube Q4 is connected to the second control terminal, the source of Q4 is grounded, the drain of Q4 is connected to one end of the second resistor R2, and the other end of R2 is connected to the output of U1. The output of the power saving circuit provides the product with an operating voltage VCC.

[0033] In one embodiment, the first switch tube and the fourth switch tube are NMOS tubes, and the second switch tube and the third switch tube are PMOS tubes.

[0034] In one embodiment, the first control terminal inputs a first control signal, and the first control signal is a 5V voltage provided when the USB cable is inserted into the USB interface. When the first control terminal inputs the first control signal, the first switch tube Q1 is turned on, thereby turning on the second switch tube Q2 and the third switch tube Q3, and the enable pins of the first power control chip U1 and the second power control chip U2 are pulled to a high level. At this time, the output pins of U1 and U2 can output normally, that is, the circuit conduction from the battery to the working voltage is realized; at this time, even if the input of the first control signal stops, the output pin of U1 continues to provide a high level for the enable pins of U1 and U2 through the second resistor R2, so that U1 and U2 are continuously turned on.

[0035] In one embodiment, the second control terminal inputs a second control signal, the second control signal is a high level signal, and the second control signal input by the second control terminal is triggered by at least one of the following operations: long pressing a single key, long pressing a combination of keys, and the communication terminal sending a control instruction.

[0036] In one embodiment, when the second control terminal inputs the second control signal, the fourth switch tube Q4 is turned on, and the enable pins of the first power control chip U1 and the second power control chip U2 are pulled down to GND. At this time, U1 and U1 stop outputting, realizing the circuit disconnection from the battery to the working voltage.

[0037] In one embodiment, when it is necessary to measure the leakage current of the internal circuit from the USB interface, firstly, the second control terminal outputs a high level, turns on the fourth switch tube Q4, and disconnects the outputs of U1 and U2; then, a customized USB cable without 5V voltage is plugged in, the D+ of the external USB cable is connected to VCC, and the D- is connected to VBAT, and the ammeter is connected in series between D+ and D- to test the leakage current of the internal circuit.

[0038] Figure 2 What is shown is a specific implementation circuit diagram of the power-saving circuit of the present invention. Based on the circuit diagram, the working principle of the power-saving circuit of the present invention is specifically explained.

[0039] 1. Enter transport mode from normal mode.

[0040] Through the software logic control of the product (such as long pressing a certain button, or long pressing a certain combination of keys, or the communication terminal sending a control instruction), the second control terminal PF6 is controlled to output a high level, Q12 is turned on, and the EN pins of U12 and U13 are pulled down to GND. At this time, U12 and U13 stop outputting, that is, the VCC output is 0, and the circuit from VBAT to VCC is disconnected (that is, shipping mode).

[0041] 2. Enter normal mode from transport mode.

[0042] When the 5V USB cable is inserted, 5V will turn on Q11, thereby turning on Q13 and Q10 (Q10 parasitic diode automatically turns on), and the EN pins of U12 and U13 are pulled to a high level, thereby enabling the output of U12 and U13. At this time, the VOUT pins of U12 and U13 can output the VBAT voltage normally, that is, the circuit conduction from VBAT to VCC is realized. When the 5V USB is unplugged, the VOUT of U12 continues to provide a high level to the EN pins of U12 and U13 through R77, so that U12 and U13 continue to conduct.

[0043] 3. Leakage current measured through USB interface from shipping mode.

[0044] When it is necessary to measure the static current (i.e. leakage current) of the internal circuit from the USB interface, first make PF6 output high level, turn on Q12, and disconnect U12 and U13 from output. At this time, plug in the customized USB cable (without 5V voltage), such as Figure 3 As shown, the D+ of the external USB cable is connected to VCC, and the D- is connected to VBAT. The ammeter is connected in series between D+ and D- to test the leakage current of the internal circuit.

[0045] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention. For ordinary technicians in this field, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A transport mode power saving circuit, characterized in that: The power saving circuit includes: a first power management chip U1, a second power management chip U2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first resistor R1, a second resistor R2 and a third resistor R3; wherein the input pin of the first power management chip U1 is connected to the output of the battery, the output pin of U1 is connected to the input pin of the second power management chip U2, and the output pin of U2 serves as the output of the power saving circuit; the gate of the first switch tube Q1 is connected to the first control terminal, the source of Q1 is grounded, and the drain of Q1 is connected to the ground. The gate of Q2 is connected to the gate of the second switch tube Q2, and the first resistor R1 is also connected between the gate and source of Q1; the gate of Q2 is also connected to the output of the battery through the third resistor R3, the source of Q2 is connected to the output of the battery, and the drain of Q2 is connected to the drain of the third switch tube Q3; the gate of Q3 is grounded, and the drain of Q3 is respectively connected to the enable pins of U1 and U2; the gate of the fourth switch tube Q4 is connected to the second control end, the source of Q4 is grounded, the drain of Q4 is connected to one end of the second resistor R2, and the other end of R2 is connected to the output end of U1.

2. The power saving circuit according to claim 1, wherein: The output of the power saving circuit provides the operating voltage VCC for the product.

3. The power saving circuit according to claim 1, wherein: The first switch tube and the fourth switch tube are NMOS tubes, and the second switch tube and the third switch tube are PMOS tubes.

4. The power saving circuit according to claim 1, wherein: The first control end inputs a first control signal, where the first control signal is a 5V voltage provided when a USB cable is inserted into a USB interface.

5. The power saving circuit according to claim 1, wherein: When the first control terminal inputs the first control signal, the first switch tube Q1 is turned on, thereby turning on the second switch tube Q2 and the third switch tube Q3, and the enable pins of the first power control chip U1 and the second power control chip U2 are pulled to a high level. At this time, the output pins of U1 and U2 can output normally, that is, the circuit conduction from the battery to the working voltage is realized; at this time, even if the input of the first control signal stops, the output pin of U1 continues to provide a high level for the enable pins of U1 and U2 through the second resistor R2, so that U1 and U2 continue to be turned on.

6. The power saving circuit according to claim 1, wherein: The second control terminal inputs a second control signal, and the second control signal is a high level signal.

7. The power saving circuit according to claim 6, wherein: The second control signal input by the second control terminal is triggered by at least one of the following operations: long pressing a single key, long pressing a combination of keys, and the communication terminal sending a control instruction.

8. The power saving circuit according to claim 1, wherein: When the second control terminal inputs the second control signal, the fourth switch tube Q4 is turned on, and the enable pins of the first power control chip U1 and the second power control chip U2 are pulled down to GND. At this time, U1 and U1 stop outputting, realizing the circuit disconnection from the battery to the working voltage.

9. The power saving circuit according to claim 1, wherein: When it is necessary to measure the leakage current of the internal circuit from the USB interface, first output the high level of the second control terminal to turn on the fourth switch tube Q4, so that U1 and U2 disconnect the output; then plug in the customized USB cable without 5V voltage, connect the D+ of the external USB cable to VCC, and the D- to VBAT, connect the ammeter in series between D+ and D-, and test the leakage current of the internal circuit.

Images