CN210898936U

CN210898936U - DC power output adjustable circuit

Info

Publication number: CN210898936U
Application number: CN201921590489.7U
Authority: CN
Inventors: 蔡佳; 朱锌铧; 涂柏生
Original assignee: Changsha Boxin Microelectronics Technology Co ltd
Current assignee: Changsha Boxin Microelectronics Technology Co ltd
Priority date: 2019-09-24
Filing date: 2019-09-24
Publication date: 2020-06-30
Anticipated expiration: 2029-09-24

Abstract

The utility model discloses a DC power output adjustable circuit, which comprises a L1, a D1 and a U1 which are connected between Vin and Vout; the FB pin of the U1 is connected with Vout through R2; the FB pin of U1 is grounded through R3; the FB pin of U1 is grounded through series R4 and C3; Vout-PWM is connected between R4 and C3 through R5; the utility model discloses can realize the arbitrary control to output voltage size, and it is simple to have the principle, and is with low costs, advantages such as portability height.

Description

DC power output adjustable circuit

Technical Field

The utility model belongs to the technical field of voltage adjustable circuit, specifically be a DC power output adjustable circuit.

Background

With the popularization of electronic products, there is a higher requirement for voltage output adjustment in corresponding circuit design, and electronic devices commonly used in the chip industry, such as a burner, a compiler, a development board, etc., are taken as examples. Because different chips require different burning voltages, the burning compiling equipment needs to adjust the output voltage.

The current commonly used method comprises 1, directly outputting a plurality of groups of voltages with different sizes by using a pin header, and connecting a user with an external jumper. 2. The internal voltage output is adjusted by the aid of the external adapter card and the resistance voltage division ratio on the adapter card. 3. That is, in the prior art described in the second section below, the output voltage is adjusted by setting multiple sets of voltage division ratios of resistors inside the board and then controlling the voltage division ratios through multiple IO ports.

Fig. 1 is a prior art scheme, and the disadvantage of this scheme is that a resistor and an IO port need to be added for each increase of a voltage level, and as the number of output voltage levels increases, the corresponding resistor and IO port also need to be added, thus occupying more chip resources, increasing the cost, and simultaneously increasing the difficulty of PCB layout wiring.

The schemes have the defects of more or less complex structure, complex operation, complex circuit, occupation of more internal resources of the single chip microcomputer, higher cost, no portability, capability of determining voltage output by hardware, incapability of randomly adjusting and the like.

SUMMERY OF THE UTILITY MODEL

The utility model aims at above problem, provide a DC power output adjustable circuit, it can realize the arbitrary control to output voltage size, and has that the principle is simple, and is with low costs, advantages such as portability height.

In order to realize the above purpose, the utility model adopts the technical scheme that: a DC power output adjustable circuit comprises an inductor L1 connected between an input voltage Vin and an output voltage Vout, a freewheeling diode D1 and a boost chip U1; the FB pin of the boost chip U1 is connected with the output voltage Vout through a first feedback resistor R2; the FB pin of the boost chip U1 is grounded through a second feedback resistor R3; the FB pin of the boosting chip U1 is grounded through a third feedback resistor R4 and a third capacitor C3 which are connected in series; the IO port Vout-PWM of the single chip microcomputer is connected between the third feedback resistor R4 and the third capacitor C3 through a resistor R5.

Further, the input voltage Vin is grounded through the second capacitor C2; the output voltage Vout is connected to ground via a first capacitor C1.

Further, the EN pin of the boost chip U1 is connected to the EN signal through a protection resistor R1.

The utility model has the advantages that:

1. the utility model discloses the scheme only needs few component to and 1 singlechip IO mouth can realize the arbitrary control to output voltage size through software, and the principle is simple, and is with low costs, advantages such as portability height.

2. The scheme also has the advantages of arbitrary adjustability of output voltage and good output smoothness.

Drawings

Fig. 1 is a schematic diagram of the circuit structure of the present invention.

Fig. 2 is a schematic diagram of a circuit structure of the prior art.

In the figure: u1 is a boost chip; c2 is an input filter capacitor; l1 is an inductor; d1 is a freewheeling diode; c1 is an output filter capacitor; R2/R3/R4 is a feedback resistor; r5 and C3 form an RC filter circuit; Vout-PWM is a singlechip IO port; vin is the input voltage; vout is the output voltage.

Detailed Description

In order to make the technical solution of the present invention better understood, the present invention is described in detail below with reference to the accompanying drawings, and the description of the present invention is only exemplary and explanatory, and should not be construed as limiting the scope of the present invention.

As shown in fig. 1, the specific structure of the present invention is: a DC power output adjustable circuit comprises an inductor L1 connected between an input voltage Vin and an output voltage Vout, a freewheeling diode D1 and a boost chip U1; the FB pin of the boost chip U1 is connected with the output voltage Vout through a first feedback resistor R2; the FB pin of the boost chip U1 is grounded through a second feedback resistor R3; the FB pin of the boosting chip U1 is grounded through a third feedback resistor R4 and a third capacitor C3 which are connected in series; the IO port Vout-PWM of the single chip microcomputer is connected between the third feedback resistor R4 and the third capacitor C3 through a resistor R5.

Preferably, the input voltage Vin is grounded through the second capacitor C2; the output voltage Vout is connected to ground via a first capacitor C1.

Preferably, the EN pin of the boost chip U1 is connected to the EN signal through a protection resistor R1.

The specific principle flow is as follows:

inside the DC BOOST chip is a typical BOOST circuit, which is not described in detail here, and only the setting of the magnitude of its output voltage is discussed here. When the single-chip microcomputer IO port Vout-PWM floats empty and does not output signals, the output voltage Vout is determined by the voltage division ratio of the feedback resistor R2/R3, namely Vout =0.6(1+ R2/R3). When the single-chip microcomputer IO port Vout-PWM outputs a PWM signal with fixed frequency and adjustable duty ratio, the signal is filtered by R5/C3 to obtain a stable adjustable voltage which changes along with the adjustment of the duty ratio at a point b, and as the voltage at the point a is fixed at 0.6V, the Vout voltage is reduced along with the rise of the voltage at the point b according to the kirchhoff current law (Vb-0.6)/R4 + (Vout-0.6)/R2 = 0.6/R3. The voltage at the point b can be adjusted by adjusting the duty ratio through the IO port, so that the adjustment of the output voltage can be realized through one IO port in the scheme.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

The principles and embodiments of the present invention have been explained herein using specific examples, which are presented only to assist in understanding the methods and their core concepts. The foregoing is only a preferred embodiment of the present invention, and it should be noted that there are objectively infinite specific structures due to the limited character expressions, and it will be apparent to those skilled in the art that a plurality of modifications, decorations or changes can be made without departing from the principle of the present invention, and the above technical features can be combined in a proper manner; the application of these modifications, variations or combinations, or the application of the concepts and solutions of the present invention in other contexts without modification, is not intended to be considered as a limitation of the present invention.

Claims

1. A DC power output adjustable circuit comprises an inductor L1 connected between an input voltage Vin and an output voltage Vout, a freewheeling diode D1 and a boost chip U1; the boost circuit is characterized in that an FB pin of the boost chip U1 is connected with an output voltage Vout through a first feedback resistor R2; the FB pin of the boost chip U1 is grounded through a second feedback resistor R3; the FB pin of the boosting chip U1 is grounded through a third feedback resistor R4 and a third capacitor C3 which are connected in series; the IO port Vout-PWM of the single chip microcomputer is connected between the third feedback resistor R4 and the third capacitor C3 through a resistor R5.

2. The adjustable circuit of claim 1, wherein the input voltage Vin is grounded through a second capacitor C2; the output voltage Vout is connected to ground via a first capacitor C1.

3. The adjustable DC power output circuit as claimed in claim 1, wherein the EN pin of the boost chip U1 is connected to the EN signal through a protection resistor R1.