TW201816402A - Buck-boost electric power conversion circuit having a center-tapped transformer element for sensing induction current and a signal rectification unit - Google Patents

Abstract

A buck-boost electric power conversion circuit includes a first active switch, a second active switch, an inductor, a center-tapped transformer element, and a signal rectification unit. The first active switch is connected in series with the second active switch to form a circuit branch connected in parallel with an electric power input source. The inductor is connected with a capacitor. The center-tapped transformer element includes a primary winding and a secondary winding. Two ends of the primary winding are respectively connected to the first active switch and the second active switch. The primary winding has a tap end connected to the inductor. The primary winding supplies electric power to the inductor when the first active switch or the second active switch is turned on. The secondary winding generates magnetic induction to generate a magnetic induction signal. The signal rectification unit is connected to the secondary winding for receiving the magnetic induction signal and performing rectification to generate a current sensing signal.

Description

Buck-boost power conversion circuit

The invention relates to a step-up and step-down power conversion circuit, in particular to a step-up and step-down power conversion circuit with a center-tap specific current element built to sense the inductor current.

With the development of the electronics industry, in addition to the original functions, many circuits require more stable control of the circuits. Among them, the buck-boost power conversion circuit is shown in Figure 1. Today, in order to confirm the buck-boost type, The current of an inductor 301 in the power conversion circuit 300 is measured using a Hall element 302, and the Hall element 302 is connected in series with the inductor 301 to obtain an inductor current. However, the Hall element 302 is generally relatively large and It will occupy more wiring space, which is not conducive to the miniaturization of today's electronic equipment. Furthermore, the cost of the Hall element 302 is higher, which will increase the cost of the overall circuit.

In addition to the above embodiments, the Republic of China Publication No. 201621505 discloses a power supply control circuit including an emulator circuit. The simulator circuit includes a first input terminal and a second input terminal. The first input terminal is used to receive a first input value. The first input value indicates an input voltage used by a power supply circuit to generate an output voltage. Powered by each load, the second input terminal is used to receive a second input value, and the second input value indicates the magnitude of the output voltage generated by the power supply circuit. The patent uses the current simulator circuit to simulate the current flowing through the inductor of the power supply circuit by using the magnitude of the input voltage and the magnitude of the output voltage. Of course, although the patent can obtain the current of the inductor, the disclosed circuit is very cumbersome and not conducive to application.

The main purpose of the present invention is to solve the problems existing in the conventional embodiments.

To achieve the above object, the present invention provides a buck-boost power conversion circuit, which is connected to a power input source and receives power provided by the power input source. The step-up and step-down power conversion circuit includes a first active switch, a second active switch, an inductor, a center-tap specific current component, and a signal rectifying unit. The first active switch is connected in series to the second active switch to form a branch. The branch is connected in parallel to the power input source. The inductor is connected to a capacitor. The center-tap current-concentration element includes a primary winding and a primary winding. The primary winding has two ends connected to the first active switch and the second active switch. The primary winding has a tap end connected to the inductor. The primary winding is connected to the first active switch or the second active switch. When the active switch is turned on, power is supplied to the inductor through the tap end, and the secondary winding generates magnetic induction at the same time to generate a magnetic induction signal. The signal rectification unit is connected to the secondary winding, receives the magnetic induction signal and rectifies to generate a magnetic induction signal. A current sensing signal corresponding to the current of the inductor.

In an embodiment, the center-tap specific current element includes a first sub-winding connected to the first active switch and the tap end, and a second sub-winding connected to the second active switch and the tap end, respectively. Child winding.

In one embodiment, the signal rectifier unit includes a conversion resistor connected in parallel to the secondary winding, and a rectifier circuit connected in parallel to the conversion resistor.

In one embodiment, the rectifier circuit is a full-wave rectifier circuit or a half-wave rectifier circuit.

In one embodiment, the signal rectifying unit includes a voltage regulating unit connected in parallel to the rectifying circuit.

In one embodiment, the buck-boost power conversion circuit includes an on / off control unit that connects the first active switch and the second active switch.

In one embodiment, the second active switch is a transistor, a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor.

The embodiment disclosed by the present invention has the following characteristics compared with the conventional one: The present invention can generate the magnetic induction through the center-tap specific current element regardless of whether the first active switch and the second active switch are turned on or not. The magnetic sensing signal can be rectified to obtain the current sensing signal corresponding to the current of the inductor, so that engineers can understand the current change of the inductor through the current sensing signal. In addition, the conventional components disclosed in the present invention are too bulky, costly, and complicated.

The detailed description and technical contents of the present invention are described below with reference to the drawings:

Please refer to FIG. 2 and FIG. 3. The present invention provides a buck-boost power conversion circuit 1. The buck-boost power conversion circuit 1 is connected to a power input source 2 and receives the power provided by the power input source 2 and converts it into a job. electric power. Further, the power input source 2 may be a DC power source or an AC power source. Furthermore, when the power input source 2 is the AC power source, a converter needs to be provided between the buck-boost power conversion circuit 1 and the AC power source to convert the working power that is AC to DC. As mentioned above, the step-up and step-down power conversion circuit 1 includes a first active switch 11, a second active switch 12, an inductor 13, a center-tap ratio current element 14, and a signal rectifying unit 15. The first active switch 11 is connected in series to the second active switch 12 and forms a branch 16. The branch 16 is connected in parallel to the power input source 2. Further, the first active switch 11 may be a transistor, a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor, and the second active switch 12 may also be the transistor, the A metal oxide semiconductor field effect transistor or the insulated gate bipolar transistor. Furthermore, in the present invention, the first active switch 11 and the second active switch 12 are implemented by the same switching element, that is, when the first active switch 11 is the transistor, the second active switch 12 is also the transistor. In addition, the step-up and step-down power conversion circuit 1 further includes an on-off control unit 18 connecting the first active switch 11 and the second active switch 12. After the on-off control unit 18 is activated, it sends to the The first active switch 11 and the second active switch 12 output a control signal, so that the first active switch 11 and the second active switch 12 are turned on or off according to the control signal. Further, if the present invention wants to perform boosted energy feedback on the power provided by the power input source 2, the first active switch 11 can be made later than the second active switch by reversing the pulse wave output by the control signal. The source switch 12 enters a conducting state, and the two are alternately opened and closed, so that the circuit of the present invention implements a boosting operation. On the other hand, if the power provided by the power input source 2 is to be stepped down, the first active switch 11 can be brought into a conducting state earlier than the second active switch 12 through the pulse wave output by the control signal. , And make them alternately open and close, so that the circuit of the present invention implements a voltage reduction action.

The inductor 13 is connected to a capacitor 17, and both ends of the capacitor 17 can be used as the output terminal of the step-up and step-down power conversion circuit 1 of the present invention. In addition, the center-tap specific-flow element 14 includes a primary winding 141 and a primary winding 142. The turns ratio between the primary winding 141 and the secondary winding 142 can be adjusted according to implementation requirements. Further, the two ends of the primary winding 141 are respectively connected to the first active switch 11 and the second active switch 12, and the primary winding 141 has a tap end 143 connected to the inductor 13, and more specifically, the primary winding 141 has a first sub-winding 144 connected to the first active switch 11 and the tap end 143, and a second sub-winding 145 connected to the second active switch 12 and the tap end 143, respectively. On the other hand, when the primary winding 141 receives power and a current flows, the secondary winding 142 will generate magnetic induction with the primary winding 141 to generate a magnetic induction signal 146.

Please refer to FIG. 2 and FIG. 3 again. The signal rectifying unit 15 is connected to the secondary winding 142 to receive the magnetic induction signal 146 from the secondary winding 142 and rectify the magnetic induction signal 146 to generate a current sensing signal 151. The current sensing signal 151 corresponds to a current 131 of the inductor 13, which indicates that the current 131 of the inductor 13 changes. Furthermore, the signal rectifier unit 15 includes a conversion resistor 152 connected in parallel to the secondary winding 142 and a rectifier circuit 153 connected in parallel to the conversion resistor 152. Among them, the conversion resistor 152 changes the characteristics of the magnetic induction signal 146, so that its current characteristics are obvious and beneficial to the operation of the rectifier circuit 153. In addition, the rectifier circuit 153 may be a half-wave rectifier circuit or a full-wave rectifier circuit. The structure in which the rectifier circuit 153 is implemented by a half-wave rectifier circuit is shown in FIG. 2. Shown in Figure 3. In an embodiment, the signal rectifying unit 15 further includes a voltage regulating unit 154 connected in parallel to the rectifying circuit 153. A subsequent stage of the voltage regulating unit 154 can be connected to a signal processing unit (not shown in the figure). The signal processing The unit must accept the current sensing signal 151 to perform the reservation processing set by the signal processing unit. Further, the voltage regulating unit 154 is actually a voltage dividing circuit, and the voltage regulating unit 154 can perform a corresponding resistance value ratio according to a signal voltage value allowed by the signal processing unit.

According to the invention, during the power-on implementation process of the present invention, the first active switch 11 and the second active switch 12 will be controlled by the on-off control unit 18 to generate corresponding opening and closing actions. The switch 11 is turned on, and when the second active switch 12 is turned off, a current flows through the first sub-winding 144 to generate magnetic induction with the secondary winding 142, so that the secondary winding 142 generates the magnetic induction signal 146. On the other hand, when the second active switch 12 is turned on and the first active switch 11 is turned off, a current flows through the second sub-winding 145 to generate magnetic induction with the secondary winding 142, so that the secondary winding 142 The magnetic induction signal 146 is generated. Therefore, the center-tap ratio current element 14 of the present invention can accept the current 131 flowing to the inductor 13 regardless of whether the first active switch 11 and the second active switch 12 are turned on or not, and can specifically generate The magnetic induction signal 146 allows the magnetic induction signal 146 to fully represent the change in the current 131 of the inductor 13.

Furthermore, the present invention then uses the circuit disclosed in FIG. 2 to perform circuit simulation in continuous conduction mode (CCM), critical conduction mode (CRM), and discontinuous conduction mode (DCM), and the current 131 and the magnetic induction of the inductor 13 The signal 146 and the current sensing signal 151 are as shown in FIGS. 4 to 6. However, it can be understood from the waveforms disclosed in FIGS. 4 to 6 that the waveform of the current sensing signal 151 is equivalent to the waveform of the current 131 of the inductor 13. In this way, it can be proved that the structure disclosed in the present invention is indeed used to sense the current 131 of the inductor 13.

The present invention has been described in detail above, but the above is only a preferred embodiment of the present invention. When the scope of implementation of the present invention cannot be limited by this, that is, all equality made in accordance with the scope of patent application of the present invention Changes and modifications should still be covered by the patent of the present invention.

1‧‧‧Buck-Boost Power Conversion Circuit

11‧‧‧The first active switch

12‧‧‧Second Active Switch

13‧‧‧Inductance

131‧‧‧ current

14‧‧‧ Center Tap Specific Flow Element

141‧‧‧Primary winding

142‧‧‧ secondary winding

143‧‧‧Tap

144‧‧‧First Sub Winding

145‧‧‧Second Sub Winding

146‧‧‧ Magnetic induction signal

15‧‧‧Signal Rectifier Unit

151‧‧‧Current sensing signal

152‧‧‧ Conversion resistor

153‧‧‧Rectifier circuit

154‧‧‧Pressure regulating unit

16‧‧‧ branch road

17‧‧‧Capacitor

18‧‧‧Open / close control unit

2‧‧‧ Electricity input source

300‧‧‧Step-up and step-down power conversion circuit

301‧‧‧Inductance

302‧‧‧Hall element

Figure 1. Schematic diagram of a conventional circuit. FIG. 2 is a schematic circuit diagram of an embodiment of the present invention. FIG. 3 is a schematic circuit diagram of another embodiment of the present invention. FIG. 4 is a schematic waveform diagram simulated in a continuous conduction mode according to an embodiment of the present invention. FIG. 5 is a schematic waveform diagram simulated in a critical conduction mode according to an embodiment of the present invention. FIG. 6 is a waveform diagram simulated in a discontinuous conduction mode according to an embodiment of the present invention.

Claims (9)

A buck-boost power conversion circuit connected to a power input source and receiving power provided by the power input source includes: a first active switch and a second active switch. The first active switch is connected in series with the first active switch. A second active switch forms a branch, the branch is connected in parallel to the power input source; an inductor is connected to a capacitor; a center-tapped specific current element includes a primary winding and a primary winding, and the primary winding has two ends The first active switch and the second active switch are respectively connected, and the primary winding has a tap end connected to the inductor, and the primary winding passes the tap when the first active switch or the second active switch is turned on. The terminal supplies power to the inductor, and the secondary winding generates magnetic induction at the same time to generate a magnetic induction signal; and a signal rectifying unit connected to the secondary winding, accepts the magnetic induction signal and rectifies to generate a current corresponding to the inductance. Current sensing signal. The buck-boost power conversion circuit according to claim 1, wherein the center-tap specific current element includes a first sub-winding connected to the first active switch and the tap end, and a second sub-winding respectively connected to the second active switch and the tap end. A source switch and a second sub-winding connected to the tap end. The step-up and step-down power conversion circuit according to claim 1 or 2, wherein the signal rectifying unit includes a conversion resistor connected in parallel with the secondary winding and a rectifier circuit connected in parallel with the conversion resistor. The buck-boost power conversion circuit according to claim 3, wherein the rectifier circuit is a full-wave rectifier circuit or a half-wave rectifier circuit. The buck-boost power conversion circuit according to claim 4, wherein the signal rectifying unit includes a voltage regulating unit connected in parallel to the rectifying circuit. The step-up and step-down power conversion circuit according to claim 3, wherein the step-up and step-down power conversion circuit includes an on-off control unit that connects the first active switch and the second active switch. The step-up and step-down power conversion circuit according to claim 1 or 2, wherein the step-up and step-down power conversion circuit includes an on-off control unit that connects the first active switch and the second active switch. The buck-boost power conversion circuit according to claim 1, wherein the first active switch is a transistor, a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor. The buck-boost power conversion circuit according to claim 1, wherein the second active switch is a transistor, a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor.