Portable device dual power supply switching system

Abstract

The present invention provides a dual-power supply switching system for portable devices, including a load switch U1, an NMOS tube Q2, a PMOS tube Q3, a clamping diode D4, a resistor R9, a resistor R8, and a resistor R7. Pins 1 and 2 of the load switch U1 are respectively connected to the main power supply VBAT_M, pins 6 and 7 of the load switch U1 are respectively connected to the S pole of the NMOS tube Q2, the D pole of the NMOS tube Q2 is connected to the system power supply VSYS, the G pole of the NMOS tube Q2 is connected to the G pole of the PMOS tube Q3 after being connected in series with resistors R9 and R8, the S pole of the PMOS tube Q3 is connected to the auxiliary power supply VBAT_S, and the D pole of the PMOS tube Q3 is connected to the system power supply VSYS. The beneficial effects of the present invention are: a simplified switching scheme is adopted, the development cycle is reduced, the firmware cost is reduced, the product versatility is improved, and a universal, fast, and efficient solution is provided for the uninterrupted power supply of portable device systems.

Description

Technical Field

[0001] The invention relates to a power supply switching system, and in particular to a dual power supply switching system for portable equipment. Background Art

[0002] In order to achieve long-term uninterrupted operation of portable devices (such as vehicle-mounted locators and law enforcement instruments), when one side's power is exhausted or other factors require power outage, it is necessary to switch the system power supply to the backup power supply. Traditional uninterruptible power supply (UPS) designs all use highly integrated power management chips or dedicated dual power switching management chips. These two designs: the former has high development costs and complex control and detection circuits. The latter is not very versatile, has a high degree of software dependence, and has a long development and certification cycle. In particular, the dedicated dual power switching management chip is very prone to the risk of supply interruption due to its own production capacity limitations, and there is no similar product on the market to replace it. This poses a fatal hidden danger to the later mass production of the product.

[0003] Therefore, how to effectively shorten the development cycle, reduce firmware costs, and improve product versatility is a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention provides a dual power supply switching system for a portable device.

[0005] The present invention provides a dual-power supply switching system for a portable device, comprising a load switch U1, an NMOS tube Q2, a PMOS tube Q3, a clamping diode D4, a resistor R9, a resistor R8, and a resistor R7, wherein pins 1 and 2 of the load switch U1 are respectively connected to a main power supply VBAT_M, pins 6 and 7 of the load switch U1 are respectively connected to the S pole of the NMOS tube Q2, the D pole of the NMOS tube Q2 is connected to a system power supply VSYS, the G pole of the NMOS tube Q2 is connected to the G pole of the PMOS tube Q3 after being connected in series with resistors R9 and R8, the S pole of the PMOS tube Q3 is connected to an auxiliary power supply VBAT_S, the D pole of the PMOS tube Q3 is connected to the system power supply VSYS, the pins 8 of the load switch U1 are respectively connected to the clamping diodes D4, and the resistors R9, R8, and R7 are ... pins 1 and 2 of the load switch U1 are respectively connected to the S pole of the NMOS tube Q2, and the D pole of the NMOS tube Q2 is connected to the system power supply VSYS, the pins 6 and 7 of the load switch U1 are respectively connected to the S pole of the NMOS tube Q2, and the D pole of the NMOS tube Q2 is connected to the system power supply VSYS, the pins 8 and 8 of the load switch U1 are respectively connected to the clamping diodes D4, and the pins 8 and 7 of the load switch U1 are respectively connected to the S pole of the NMOS tube Q2, and the D pole of the NMOS tube Q2 is connected to the system power supply VSYS, the pins 6 and 7 of the load switch U1 are respectively connected to the S pole of The anode of D4 and the G electrode of NMOS tube Q2 are connected, the cathode of the clamping diode D4 is respectively connected to one end of the resistor R7 and the G electrode of PMOS tube Q3, and the other end of the resistor R7 is connected to the auxiliary power supply VBAT_S; in a normal state, when the main power supply VBAT_M is output, through the load switch U1, the pin 8 of the load switch U1 generates a continuous high level signal, so that the NMOS tube Q2 is in a conducting state, and at the same time, the GT signal causes the clamping diode D4 to set the gate of the PMOS tube Q3 high, and the PMOS tube Q3 works in a cut-off state, and the system power supply VSYS is provided by the main power BAT_M at this time; when the main power supply BAT_M is removed, the output control level of the pin 8 of the load switch U1 disappears, the NMOS tube Q2 is cut off, and the clamping diode D4 loses its function. After the auxiliary power supply VBAT_S is divided, the PMOS tube Q3 is in a conducting state, and the system power supply VSYS is switched to the auxiliary power supply VBAT_S.

[0006] As a further improvement of the present invention, the portable device dual power supply switching system also includes a capacitor C5 and a capacitor C11, one end of the capacitor C5 is connected to the main power supply VBAT_M and the other end is grounded, and one end of the capacitor C11 is connected to the system power supply VSYS and the other end is grounded.

[0007] As a further improvement of the present invention, the dual power supply switching system for portable devices also includes a resistor R6 and a resistor R10, one end of the resistor R6 is connected to the main power supply VBAT_M, and the other end is connected to pin 9 of the load switch U1, one end of the resistor R10 is connected to pin 4 of the load switch U1, and the other end is grounded.

[0008] As a further improvement of the present invention, the portable device dual power supply switching system also includes an internal charging circuit, and the internal charging circuit includes a battery charging chip U15, pin 4 of the battery charging chip U15 is connected to the main power supply VBAT_M, and pin 5 of the battery charging chip U15 is connected to the auxiliary power supply VBAT_S.

[0009] The beneficial effects of the present invention are: through the above scheme, a simplified switching scheme is adopted, the development cycle is shortened, the firmware cost is reduced, the product versatility is improved, and a universal, fast and efficient solution is provided for the uninterrupted power supply of portable device systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The invention discloses a circuit diagram of a dual power supply switching system for a portable device.

[0011] Figure 2 It is a schematic diagram of power supply of a main power supply VBAT_M of a dual power supply switching system for a portable device of the present invention.

[0012] Figure 3 The present invention is a schematic diagram of a power supply of a secondary power supply VBAT_S of a dual-power supply switching system for a portable device. DETAILED DESCRIPTION

[0013] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0014] like Figures 1 to 3As shown, a dual power supply switching system for a portable device includes a load switch U1, an NMOS tube Q2, a PMOS tube Q3, a clamping diode D4, a resistor R9, a resistor R8, and a resistor R7. Pins 1 and 2 of the load switch U1 are respectively connected to the main power supply VBAT_M, pins 6 and 7 of the load switch U1 are respectively connected to the S pole of the NMOS tube Q2, the D pole of the NMOS tube Q2 is connected to the system power supply VSYS, the G pole of the NMOS tube Q2 is connected to the G pole of the PMOS tube Q3 after being connected in series with resistors R9 and R8, the S pole of the PMOS tube Q3 is connected to the auxiliary power supply VBAT_S, the D pole of the PMOS tube Q3 is connected to the system power supply VSYS, and pins 8 (i.e., GT pin) of the load switch U1 are respectively connected to the clamping diode D4. The anode of the clamping diode D4 and the G electrode of the NMOS tube Q2 are connected, the cathode of the clamping diode D4 is respectively connected to one end of the resistor R7 and the G electrode of the PMOS tube Q3, and the other end of the resistor R7 is connected to the auxiliary power supply VBAT_S; in a normal state, when the main power supply VBAT_M is output, through the load switch U1, the pin 8 of the load switch U1 generates a continuous high-level signal, so that the NMOS tube Q2 is in a conducting state, and at the same time, the GT signal causes the clamping diode D4 to set the gate of the PMOS tube Q3 high, and the PMOS tube Q3 works in a cut-off state, and the system power supply VSYS is provided by the main power BAT_M at this time; when the main power supply BAT_M is removed, the control level output by the pin 8 of the load switch U1 disappears, the NMOS tube Q2 is cut off, and the clamping diode D4 loses its function. After the auxiliary power supply VBAT_S is divided, the PMOS tube Q3 is in a conducting state, and the system power supply VSYS is switched to the auxiliary power supply VBAT_S.

[0015] like Figures 1 to 3 As shown, the portable device dual power supply switching system also includes a capacitor C5 and a capacitor C11, one end of the capacitor C5 is connected to the main power supply VBAT_M, and the other end is grounded, and one end of the capacitor C11 is connected to the system power supply VSYS, and the other end is grounded.

[0016] like Figures 1 to 3 As shown, the portable device dual power supply switching system also includes a resistor R6 and a resistor R10, one end of the resistor R6 is connected to the main power supply VBAT_M, and the other end is connected to pin 9 of the load switch U1, one end of the resistor R10 is connected to pin 4 of the load switch U1, and the other end is grounded.

[0017] like Figures 1 to 3As shown, the portable device dual power supply switching system also includes an internal charging circuit 101, which includes a battery charging chip U15, a resistor R12, a resistor R13, and a resistor R14. Pin 4 of the battery charging chip U15 is connected to the main power supply VBAT_M, and pin 5 of the battery charging chip U15 is connected to the auxiliary power supply VBAT_S. After the auxiliary power supply VBAT_S is discharged, it is charged to ensure that the auxiliary power supply VBAT_S is fully charged when switching next time. The charging circuit 101 can be changed or deleted according to circuit requirements.

[0018] The present invention provides a portable device dual power supply switching system, which completes the switching of the system power supply VSYS by controlling the on and off states of NMOS and PMOS in the circuit, thereby ensuring continuous operation without power outage.

[0019] The present invention provides a portable device dual power supply switching system, the specific working principle of which is as follows:

[0020] 1. If Figure 2 As shown, in normal state, the main power supply VBAT_M is output. When the power passes through the load switch U1, the 8th pin (GT) of the tube generates a continuous high level signal. This signal makes Q2 tube in the on state; at the same time, the GT signal makes the clamping diode D4 set the gate of Q3 tube high, and Q3 tube works in the off state. At this time, the system power supply VSYS is provided by the main power BAT_M.

[0021] 2. If Figure 3 As shown in the figure, when the main power supply BAT_M is removed, the output control level of the GT pin of the load switch U1 disappears. The Q2 tube is turned off; at the same time, the clamping diode D4 loses its function. After the VBAT_S voltage is divided, the Q3 tube is in the on state. The system power supply VSYS is switched to VBAT_S.

[0022] 3. After the main power supply VBAT_M is supplied again, the load switch U1 (GT pin) generates a high level. Q2 is turned on and Q3 is turned off. The system power supply VSYS is switched back to the main power supply VBAT_M. The process is as follows: Figure 2 The whole system power supply switching work is completed.

[0023] The present invention provides a dual-power supply switching system for portable devices, which reasonably controls the U1 tube to generate a high-level control signal when working, completes the control of NMOS and PMOS tubes with completely opposite working states, ensures that only one MOS tube is turned on at any time, and completes the uninterrupted power supply to the system. The entire switching process does not require software control. There is no requirement for the platform and main control chip. The accessory charging circuit 101 can be replaced or deleted according to the actual circuit design requirements. The present invention can be widely used in products such as dual lithium battery switching circuits of handheld terminal devices, OVP circuits of vehicle modules, and uninterruptible power supply circuits for shared bicycles.

[0024] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A dual power supply switching system for a portable device, characterized in that: The load switch U1 includes a load switch U1, an NMOS tube Q2, a PMOS tube Q3, a clamping diode D4, a resistor R9, a resistor R8, and a resistor R7. Pins 1 and 2 of the load switch U1 are respectively connected to the main power supply VBAT_M. Pins 6 and 7 of the load switch U1 are respectively connected to the S pole of the NMOS tube Q2. The D pole of the NMOS tube Q2 is connected to the system power supply VSYS. The G pole of the NMOS tube Q2 is connected to the G pole of the PMOS tube Q3 after being connected in series with resistors R9 and R8. The S pole of the PMOS tube Q3 is connected to the auxiliary power supply VBAT_S. The D pole of the PMOS tube Q3 is connected to the system power supply VSYS. Pin 8 of the load switch U1 is respectively connected to the anode of the clamping diode D4, the NMOS tube The G pole of Q2 is connected, the cathode of the clamping diode D4 is respectively connected to one end of the resistor R7 and the G pole of the PMOS tube Q3, and the other end of the resistor R7 is connected to the auxiliary power supply VBAT_S; in a normal state, the main power supply VBAT_M is output, and when passing through the load switch U1, the pin 8 of the load switch U1 generates a continuous high-level signal, so that the NMOS tube Q2 is in a conducting state, and at the same time, the GT signal causes the clamping diode D4 to set the gate of the PMOS tube Q3 high, and the PMOS tube Q3 works in a cut-off state, and the system power supply VSYS is provided by the main power BAT_M at this time; when the main power supply BAT_M is removed, the control level output by the pin 8 of the load switch U1 disappears, the NMOS tube Q2 is cut off, and the clamping diode D4 loses its function. After the auxiliary power supply VBAT_S is divided, the PMOS tube Q3 is in a conducting state, and the system power supply VSYS is switched to the auxiliary power supply VBAT_S; The portable device dual power supply switching system further includes a capacitor C5 and a capacitor C11, wherein one end of the capacitor C5 is connected to the main power supply VBAT_M and the other end is grounded, and one end of the capacitor C11 is connected to the system power supply VSYS and the other end is grounded; The portable device dual power supply switching system also includes a resistor R6 and a resistor R10, wherein one end of the resistor R6 is connected to the main power supply VBAT_M and the other end is connected to pin 9 of the load switch U1, and one end of the resistor R10 is connected to pin 4 of the load switch U1 and the other end is grounded.

2. The dual power supply switching system for portable devices according to claim 1, characterized in that: The portable device dual power supply switching system further includes an internal charging circuit, which includes a battery charging chip U15, wherein pin 4 of the battery charging chip U15 is connected to a main power supply VBAT_M, and pin 5 of the battery charging chip U15 is connected to a secondary power supply VBAT_S.

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