Self-switching voltage stabilizing circuit of power supply

A technology of power switching and voltage stabilizing circuits, applied in circuit devices, emergency power supply arrangements, electrical components, etc., can solve the problems of low heavy-load voltage, large light-load voltage, unstable output voltage, etc., to achieve high efficiency and flexible design Effect

CN104022647AInactive Publication Date: 2014-09-03SHANGHAI XIELIN ELECTRONICS
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-09-03
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a self-switching voltage stabilizing circuit of a power supply. The self-switching voltage stabilizing circuit comprises a voltage stabilizing unit part and a power supply switching unit, wherein an external power supply voltage input end is connected with the voltage stabilizing unit part, the voltage stabilizing unit part is connected with a power supply voltage output end through the power supply switching unit part, and the power supply switching unit part is also connected with a backup power supply positive input end. The self-switching voltage stabilizing circuit has advantage of being designed by adopting split elements and devices, so that the design is relatively flexible, an appropriate MOSFET (metal oxide semiconductor field effect transistor) is selected, a voltage stabilizing circuit with high input voltage can be designed, for example a voltage stabilizing circuit with the input voltage of 8V to 60V can be designed; meanwhile, the MOSFET is relatively high in efficiency, and the voltage stabilizing circuit with relatively large output current under the same size can be designed.
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Description

technical field

[0001] The invention relates to a voltage stabilizing circuit supporting automatic switching of external direct current and backup battery supply. Background technique

[0002] In the design of low-power instruments, 3.6V Li-SOCL2 disposable lithium batteries are often used as backup power for RTC, MCU or LCD and other low-power circuits after power failure. In the circuit design, it is necessary to design a switching circuit for the power supply selection after the external DC power supply is powered off or powered on. The conventional method is as follows: figure 1 As shown, the low-dropout linear regulator U1 and the diode switching method are used. The switching circuit adopts the diode isolation method. It must ensure that the external DC power supply voltage is greater than the battery voltage to ensure correct switching.

[0003] When the voltage stabilizing unit outputs 5V, the circuit can ensure accurate switching. However, as integrated circuits a...

Examples

Embodiment Construction

[0022] In order to make the present invention more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

[0023] combine image 3 and Figure 5 Application description, a self-switching power supply voltage stabilizing circuit provided by the present invention is composed of a voltage stabilizing circuit unit and a switching unit. In the simulation example, the voltage DC INPUT input from the external power supply voltage input terminal Vin_DC is the external DC power input, and Rsoure is used to change the DC voltage of the external DC power input unit, which can output a DC voltage of 0-60V. SW1 is a switch, which is used to simulate the switch for controlling the external DC power supply. Rload1 and Rload2 are simulation circuits for simulating light load and heavy load, and SWload is a switch for the two loads.

[0024] The external DC input is connected to the drain of the first NMOS transistor Q1 through SW1, the first resist...