Boost circuit with adjustable output voltage

Abstract

The utility model provides a boost circuit with adjustable output voltage, which comprises a boost chip, and an FB port of the boost chip is respectively connected with a common grounding end through three voltage regulating circuits which are connected in parallel. Each voltage regulating circuit comprises a resistor and a transistor which are connected in series. In each voltage regulating circuit, one end of a resistor is connected with an FB port, and the other end of the resistor is connected with a drain electrode of a transistor; the source electrode of the transistor is connected with the common grounding end. The grid electrode of the transistor is connected with a control voltage. According to the utility model, different I / O ports can be controlled through the MCU, and different N-channel enhanced field effect transistors are controlled, so that different output voltage requirements can be realized by only one boost chip, and the requirements of obtaining different voltages can be met while the cost and the space of components are saved.

Description

Technical Field

[0001] The present application relates to the technical field of boost circuits, and in particular to a boost circuit with adjustable output voltage. Background Art

[0002] A normal boost circuit has a fixed output voltage. The peripheral circuit of a boost chip can only output a fixed voltage. If multiple voltages are required, several different boost circuits need to be added, which increases the number and cost of chips and peripheral components. Utility Model Content

[0003] The purpose of this utility model is achieved through the following technical solutions.

[0004] Specifically, the utility model provides a boost circuit with adjustable output voltage, comprising:

[0005] A boost chip, wherein the FB port of the boost chip is respectively connected to a common ground terminal through three parallel voltage regulating circuits.

[0006] Furthermore, each of the voltage regulating circuits includes a resistor and a transistor connected in series.

[0007] Furthermore, in each of the voltage regulating circuits, one end of the resistor is connected to the FB port, and the other end is connected to the drain of the transistor; the source of the transistor is connected to the common ground terminal, and the gate of the transistor is connected to a control voltage.

[0008] Furthermore, the transistor is an N-channel enhancement type field effect transistor.

[0009] Furthermore, the GND port of the boost chip is connected to the common ground, the VIN port is connected to the VIN input voltage, the EN port is connected to the VIN input voltage through an eighth resistor, and an inductor is connected between the VIN port and the SW port of the boost chip.

[0010] Furthermore, the boost circuit further comprises:

[0011] A diode, wherein the anode of the diode is connected to the SW port of the boost chip, and the cathode of the diode is connected to the voltage output terminal VOUT.

[0012] Furthermore, the boost circuit further comprises:

[0013] A first resistor is connected between the cathode of the diode and the FB port of the boost chip, and a second resistor and a third resistor are connected in series between the FB port and a common ground terminal.

[0014] Furthermore, the boost circuit further comprises:

[0015] a second capacitor connected between the cathode of the diode and the FB port of the boost chip;

[0016] The third capacitor is connected between the cathode of the diode and the common ground terminal.

[0017] Furthermore, the boost circuit further comprises:

[0018] a tenth resistor, connected between the cathode of the diode and the voltage output terminal;

[0019] The ninth resistor is connected between the voltage output terminal and the common ground terminal.

[0020] Furthermore, the boost circuit further comprises:

[0021] A bidirectional TVS diode connected between the voltage output terminal and the common ground terminal.

[0022] The advantages of the present invention are:

[0023] The utility model can control different I / O ports through the MCU and control different N-channel enhancement type field effect transistors, so that different output voltage requirements can be achieved with only one boost chip, which can save component cost and space while meeting the requirements of obtaining different voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0025] Figure 1 The utility model shows a boost circuit diagram with adjustable output voltage. DETAILED DESCRIPTION

[0026] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0027] like Figure 1As shown, a boost circuit with adjustable output voltage includes: a boost chip U1, wherein the FB port of U1 is connected to a common ground terminal VSS through three parallel voltage regulating circuits. Each voltage regulating circuit includes a resistor and a transistor connected in series. For example, in the voltage regulating circuit composed of R4 and Q1, one end of R4 is connected to the FB port, and the other end is connected to the drain of Q1. The source of Q1 is connected to VSS, and the gate is connected to a first control voltage V1. In the voltage regulating circuit composed of R5 and Q2, one end of R5 is connected to the FB port, and the other end is connected to the drain of Q2. The source of Q2 is connected to VSS, and the gate is connected to a second control voltage V2. In the voltage regulating circuit composed of R6 and Q3, one end of R6 is connected to the FB port, and the other end is connected to the drain of Q3. The source of Q3 is connected to VSS, and the gate is connected to a third control voltage V3. Q1, Q2, and Q3 are N-channel enhancement type field effect transistors.

[0028] Additionally, U1's GND port is connected to VSS, its VIN port is connected to the VIN input voltage, its EN port is connected to VIN via resistor R8, and inductor L1 is connected between U1's VIN and SW ports. The anode of diode D1 is connected to the SW port, and its cathode is connected to the voltage output terminal VOUT.

[0029] The resistor R1 is connected between the cathode of the diode D1 and the FB port, and the resistors R2 and R3 are connected in series between the FB port and VSS.

[0030] Capacitor C2 is connected between the cathode of D1 and the FB port, and capacitor C3 is connected between the cathode of D1 and VSS. Resistor R10 is connected between the cathode of D1 and the voltage output terminal. R9 is a discharge resistor connected between the voltage output terminal and VSS. The TVS1 bidirectional diode is also connected between the voltage output terminal and VSS.

[0031] like Figure 1 As shown, there are four types of output voltage circuits: when Q1, Q2, and Q3 are not working, the output is VOUT0; when Q1 is working, the output is VOUT1; when Q2 is working, the output is VOUT2; and when Q3 is working, the output is VOUT3.

[0032] For a boost circuit, the formula for calculating a normal fixed-voltage output is VOUT = (R1 / R0+1)*VFB (R0 represents the equivalent resistance of U1's FB pin to VSS). VFB is the feedback voltage, a fixed value determined by the selected boost chip.

[0033] According to the above calculation formula, adjusting the resistance value of R0 can adjust the result of VOUT. Figure 1, add three different switch circuits at the FB end, turn on Q1, Q2, Q3 through V1, V2, V3, and you can get three different VOUT voltages. At this time:

[0034] R0=(R4*(R2+R3)) / (R2+R3+R4),

[0035] Then VOUT=(R1 / ((R4*(R2+R3)) / (R2+R3+R4))+1)*VFB

[0036] R2 and R3 can be combined into one resistor R0. These two resistors are used to improve the output VOUT accuracy.

[0037] The boost chip VIN input range required by this utility model is 2.5V-5.5V, the output voltage can reach 40V, and the VFB options are 0.1 / 0.2 / 0.25 / 0.3 / 0.6V.

[0038] TVS1 is a voltage-stabilizing diode that protects other components in the circuit from overvoltage. A TVS diode is a transient voltage suppression diode.

[0039] V1, V2, and V3 correspond to different output voltages, VOUT1, VOUT2, and VOUT3, respectively. When Q1, Q2, and Q3 are all inoperative, the output voltage is VOUT0. For example, to achieve the desired output voltage of VOUT1, V1 must exceed the gate voltage of the N-channel enhancement mode field effect transistor (this voltage is the fixed gate voltage of the N-channel enhancement mode field effect transistor, such as 2.1V), while V2 and V3 must be below 2.1V. To achieve the desired output voltage of VOUT0, V1, V2, and V3 must all be below 2.1V.

[0040] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A boost circuit with adjustable output voltage, characterized in that: include: A boost chip, wherein the FB port of the boost chip is respectively connected to a common ground terminal through three parallel voltage regulating circuits.

2. The boost circuit with adjustable output voltage according to claim 1, characterized in that: Each of the voltage regulating circuits includes a resistor and a transistor connected in series.

3. A boost circuit with adjustable output voltage according to claim 1 or 2, characterized in that: In each of the voltage regulating circuits, one end of the resistor is connected to the FB port, and the other end is connected to the drain of the transistor; the source of the transistor is connected to the common ground terminal, and the gate of the transistor is connected to a control voltage.

4. The boost circuit with adjustable output voltage according to claim 2, wherein: The transistor is an N-channel enhancement type field effect transistor.

5. A boost circuit with adjustable output voltage according to claim 1 or 2, characterized in that: The GND port of the boost chip is connected to the common ground terminal, the VIN port is connected to the VIN input voltage, the EN port is connected to the VIN input voltage through an eighth resistor, and an inductor is connected between the VIN port and the SW port of the boost chip.

6. A boost circuit with adjustable output voltage according to claim 1 or 2, characterized in that: The boost circuit further comprises: A diode, wherein the anode of the diode is connected to the SW port of the boost chip, and the cathode of the diode is connected to the voltage output terminal VOUT.

7. The boost circuit with adjustable output voltage according to claim 6, characterized in that: The boost circuit further comprises: A first resistor is connected between the cathode of the diode and the FB port of the boost chip; The second resistor and the third resistor are connected in series between the FB port and the common ground terminal.

8. The boost circuit with adjustable output voltage according to claim 6, characterized in that: The boost circuit further comprises: A second capacitor is connected between the cathode of the diode and the FB port of the boost chip; The third capacitor is connected between the cathode of the diode and the common ground terminal.

9. The boost circuit with adjustable output voltage according to claim 6, characterized in that: The boost circuit further comprises: The tenth resistor is connected between the cathode of the diode and the voltage output terminal; the ninth resistor is connected between the voltage output terminal and the common ground terminal.

10. The boost circuit with adjustable output voltage according to claim 6, characterized in that: The boost circuit further comprises: A bidirectional TVS diode connected between the voltage output terminal and the common ground terminal.

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