CN108574310A - A kind of USB interface charging circuit - Google Patents
A kind of USB interface charging circuit Download PDFInfo
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- CN108574310A CN108574310A CN201710131213.1A CN201710131213A CN108574310A CN 108574310 A CN108574310 A CN 108574310A CN 201710131213 A CN201710131213 A CN 201710131213A CN 108574310 A CN108574310 A CN 108574310A
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- usb interface
- divider resistance
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Classifications
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- H02J7/0077—
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
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- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The embodiment of the present invention provides a kind of USB interface charging circuit, is related to auto parts machinery, can damage compensating charge voltage, pressure drop caused by make up line loss according to USB line so that USB charging voltages meet relevant authentication rule.The circuit, including：Divider resistance, voltage detection unit, CPU, PWM voltage modulated modules；The control terminal of PWM voltage modulated modules connects the ends PWM of the CPU, and the input terminal of the PWM voltage modulateds module is connect with power input, and the output end of the PWM voltage modulateds module is connect with the first end of the divider resistance；For receiving the pwm control signal, the duty ratio of the turn-on time of its input terminal and output end is adjusted according to the pwm control signal, to adjust the voltage of the energization pins output of the USB interface.The embodiment of the present invention is used for USB interface.
Description
Technical field
The embodiment of the present invention is related to electronic technology field more particularly to a kind of USB interface charging circuit.
Background technology
In recent years, vehicle-mounted USB (Universal Serial Bus, universal serial bus) charging is more and more extensive.Using
USB charging system structure as shown in Figure 1, main power source B/U to USB power source management module power, CPU (Central
Processing Unit, central processing unit) control USB power source management module is to USB interface power supply, and USB interface is to outside access
Equipment charge (by the power pins VBUS and grounding pin GND of USB interface) is connect, USB charge functions are realized with this.In addition
The differential data signals received (being transmitted by differential signal pin D+ and D-) can also be sent to CPU processing by USB interface.
To USB charge functions, due to USB line itself line loss, causes USB charging voltages when large current charge to decline, such as charge
Electric current 2.4A, voltage 5V, line loss 200m Ω, then equipment terminal voltage is：
5V-200m Ω × 2.4A=4.52V
MFi (Made for iOS, for a kind of certification of apple products) authentication requesting set voltage range as 4.55V~
5.21V, i.e. 4.52V are unsatisfactory for specification.
And if in order to meet MFi certifications, output voltage 5V → 5.2V is raised, then equipment terminal voltage is：
5.2V-200m Ω × 2.4A=4.72V, voltage is 5.2V when not charging, and meets specification, but close to specification limit
Value.In addition, because the sample resistance of USB power source has deviation, output voltage is caused also to have deviation, and output voltage setting is close
Specification limit value can cause to go out to will appear when lotus checks in volume production if output voltage is slightly higher to be unsatisfactory for certification rule and want
It asks.
In short, the prior art can not provide a kind of USB interface charging circuit fully meeting the requirement of certification rule.
Invention content
The embodiment of the present invention provides a kind of USB interface charging circuit, can damage compensating charge voltage according to USB line, with
Pressure drop caused by making up line loss so that USB charging voltages meet relevant authentication rule.
In a first aspect, a kind of USB interface charging circuit is provided, including：
Divider resistance, the divider resistance first end are connected to power input by PWM voltage modulated modules, described point
The second end of piezoresistance is connected to the energization pins of USB interface, and the charging current that power supply provides flows through the divider resistance to institute
Energization pins are stated, with the charging external equipment connected to the USB interface；
Voltage detection unit, the first input end of the voltage detection unit connect the first end of the divider resistance, institute
The second input terminal for stating voltage detection unit connects the second end of the divider resistance, the output end of the voltage detection unit with
CPU connections, the partial pressure value for detecting and amplifying the divider resistance generates sampled voltage, and the sampled voltage is sent to
CPU；
The output end of the first analog-to-digital conversion end connection voltage detection unit of CPU, the CPU is for receiving the voltage inspection
The sampled voltage that unit is sent is surveyed, is controlled according to the sampled voltage and generates pwm control signal, and by the ends PWM by institute
It states pwm control signal and is sent to PWM voltage modulated modules, the pwm control signal has predetermined duty ratio；
The control terminal of PWM voltage modulated modules, the PWM voltage modulateds module connects the ends PWM of the CPU, the PWM
The input terminal of voltage modulated module is connect with power input, the output end of the PWM voltage modulateds module and partial pressure electricity
The first end of resistance connects；For receiving the pwm control signal, its input terminal and output are adjusted according to the pwm control signal
The duty ratio of the turn-on time at end, to adjust the voltage of the energization pins output of the USB interface.
Optionally, the PWM voltage modulateds module includes first switch triode and second switch triode；Described first
The base stage of switching transistor is connect with the CPU, and the base stage of emitter ground connection, collector and the second switch triode connects
It connects；The emitter of the second switch triode is connect with power input, and the first end of collector and the divider resistance connects
It connects.
Optionally, it also connects between the output end of the PWM voltage modulateds module and the first end of the divider resistance
There is inductance；Between the inductance and the first end of the divider resistance, it is also associated with capacitance, described in capacitance one end connection
The first end of divider resistance, other end ground connection.
Optionally, it is also associated with zener diode between the output end and the inductance of the PWM voltage modulateds module；
The cathode of the zener diode connects the output end of the PWM voltage modulateds module, plus earth.
Optionally, further include output voltage detecting circuit, the output voltage detecting circuit includes first resistor, the second electricity
Resistance, the first end of the first resistor connect the energization pins of the USB interface, described in the second end connection of the first resistor
The first end of second resistance, the second end ground connection of the second resistance；The second end of the wherein described first resistor is also connected with described
The second analog-to-digital conversion port of CPU, the second analog-to-digital conversion port of the CPU are used to detect the partial pressure of the first resistor, with
Determine whether the voltage of the energization pins output of the USB interface meets preset condition.
Optionally, voltage detection unit includes signal amplifier, and wherein the forward end of signal amplifier connects divider resistance
First end, signal amplifier backward end connection divider resistance second end, the output end of signal amplifier connects CPU,
It is in series with feedback resistance between the reverse side and output end of middle signal amplifier.
The USB interface charging circuit that said program provides, including：Divider resistance, voltage detection unit, CPU and PWM electricity
Press modulation module；Divider resistance first end is connected to power input, the second end of divider resistance by PWM voltage modulated modules
It is connected to the energization pins of USB interface, the charging current that power supply provides flows through divider resistance to the energization pins, with to USB
The charging external equipment of interface connection；The first end of the first input end connection divider resistance of voltage detection unit, voltage detecting
The second end of the second input terminal connection divider resistance of unit, the output end of voltage detection unit is connect with CPU, for detecting simultaneously
The partial pressure value for amplifying divider resistance generates sampled voltage, and sampled voltage is sent to CPU；The first analog-to-digital conversion end of CPU connects
The output end for connecing voltage detection unit is used for the sampled voltage that receiving voltage detection unit is sent, and is controlled and is generated according to sampled voltage
Pwm control signal, and the pwm control signal is sent to by PWM voltage modulated modules by the ends PWM, pwm control signal has
Predetermined duty ratio；The ends PWM of the control terminal connection CPU of PWM voltage modulated modules, input terminal and the electricity of PWM voltage modulated modules
Source input terminal connection, the output end of the PWM voltage modulateds module are connect with the first end of the divider resistance；For receiving
Pwm control signal is stated, the duty ratio of the turn-on time of its input terminal and output end is adjusted according to the pwm control signal, to adjust
Save the voltage of the energization pins output of USB interface.CPU can determine line by detecting the electric current of divider resistance in above process
Path loss consumes, and then determines output to the pwm control signal of PWM voltage modulated modules, PWM voltages according to the partial pressure value of divider resistance
The duty ratio that modulation module is controlled the turn-on time of its input terminal and output end by pwm control signal meets USB to realize
The adjusting of the voltage of the energization pins output of mouth, due to being made up according to USB practical line loss compensating charge voltages in this process
Pressure drop caused by line loss, therefore USB charging voltages is enabled to meet relevant authentication rule.
Description of the drawings
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be in embodiment or description of the prior art
Required attached drawing is briefly described, it should be apparent that, the accompanying drawings in the following description is only some realities of the present invention
Example is applied, it for those of ordinary skill in the art, without creative efforts, can also be according to these attached drawings
Obtain other attached drawings.
Fig. 1 is the structural schematic diagram for the USB interface charging circuit that the prior art provides.
Fig. 2 is a kind of structural schematic diagram for USB interface charging circuit that the embodiment of the present invention provides.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
With reference to Fig. 2, the embodiment of the present invention provides a kind of USB interface charging circuit, including：
Divider resistance Rf, divider resistance Rf first ends are connected to power input B/U by PWM voltage modulateds module 21,
The second end of divider resistance Rf is connected to the energization pins VBUS of USB interface 22, and the charging current that power supply provides flows through partial pressure electricity
Rf to energization pins VBUS is hindered, with the charging external equipment connected to USB interface.
Voltage detection unit 23, the first end of the first input end connection divider resistance Rf of voltage detection unit 23, voltage
The second end of the second input terminal connection divider resistance Rf of detection unit 23, the output end of voltage detection unit 23 are connect with CPU,
Partial pressure value for detecting and amplifying divider resistance Rf generates sampled voltage, and sampled voltage is sent to CPU.
The output end of the first analog-to-digital conversion end AD1 connections voltage detection unit 23 of CPU24, CPU24 is used for receiving voltage
The sampled voltage that detection unit 23 is sent controls according to sampled voltage and generates pwm control signal, and controlled PWM by the ends PWM
Signal is sent to PWM voltage modulated modules, and pwm control signal has predetermined duty ratio.
PWM voltage modulateds module 21, the ends PWM of the control terminal connection CPU24 of PWM voltage modulateds module 21, PWM voltage tune
The input terminal of molding block 21 is connect with power input B/U, and the of the output end of PWM voltage modulateds module 21 and divider resistance Rf
One end connects；For receiving pwm control signal, the turn-on time of its input terminal and output end is adjusted according to pwm control signal
Duty ratio, to adjust the voltage of the energization pins output of USB interface 22.
The USB interface charging circuit that said program provides, including：Divider resistance, voltage detection unit, CPU and PWM electricity
Press modulation module；Divider resistance first end is connected to power input, the second end of divider resistance by PWM voltage modulated modules
It is connected to the energization pins of USB interface, the charging current that power supply provides flows through divider resistance to the energization pins, with to USB
The charging external equipment of interface connection；The first end of the first input end connection divider resistance of voltage detection unit, voltage detecting
The second end of the second input terminal connection divider resistance of unit, the output end of voltage detection unit is connect with CPU, for detecting simultaneously
The partial pressure value for amplifying divider resistance generates sampled voltage, and sampled voltage is sent to CPU；The first analog-to-digital conversion end of CPU connects
The output end for connecing voltage detection unit is used for the sampled voltage that receiving voltage detection unit is sent, and is controlled and is generated according to sampled voltage
Pwm control signal, and the pwm control signal is sent to by PWM voltage modulated modules by the ends PWM, pwm control signal has
Predetermined duty ratio；The ends PWM of the control terminal connection CPU of PWM voltage modulated modules, input terminal and the electricity of PWM voltage modulated modules
Source input terminal connection, the output end of the PWM voltage modulateds module are connect with the first end of the divider resistance；For receiving
Pwm control signal is stated, the duty ratio of the turn-on time of its input terminal and output end is adjusted according to the pwm control signal, to adjust
Save the voltage of the energization pins output of USB interface.CPU can determine line by detecting the electric current of divider resistance in above process
Path loss consumes, and then determines output to the pwm control signal of PWM voltage modulated modules, PWM voltages according to the partial pressure value of divider resistance
The duty ratio that modulation module is controlled the turn-on time of its input terminal and output end by pwm control signal meets USB to realize
The adjusting of the voltage of the energization pins output of mouth, due to being made up according to USB practical line loss compensating charge voltages in this process
Pressure drop caused by line loss, therefore USB charging voltages is enabled to meet relevant authentication rule.
Illustratively, with reference to shown in Fig. 2, the embodiment of the present invention provides a kind of specific connection of USB interface charging circuit
Structure：
Wherein, PWM voltage modulateds module 21 includes first switch triode M1 and second switch triode M2.
The base stage of first switch triode M1 is connect with CPU, and emitter ground connection, collector is with second switch triode M2's
Base stage connects；The emitter of second switch triode M2 is connect with power input, the first end of collector and divider resistance Rf
Connection.Wherein it is that the voltage difference met between the base stage of switching transistor and collector meets turn-on threshold voltage voltage, base
The voltage of pole and collector is usually obtained by concatenated electric resistance partial pressure, as shown in Fig. 2, the base stage of first switch triode with
It is in series between CPU between resistance R101, collector and base stage and is in series with resistance R102, wherein in CPU to PWM voltage modulated moulds
When block inputs pwm control signal, R101 and R102 to pwm control signal divide and are made base stage sum aggregate in the high level stage
Pressure difference between electrode meets turn-on threshold voltage, is wherein in series with resistance between the base stage and CPU of second switch triode
R103, collector and base stage quality inspection are in series with resistance R104, and operation principle is similar to the above no longer to be illustrated here.
In addition, to ensure the stability of electric current on USB charging circuits, in the output end and partial pressure of PWM voltage modulated modules
Lc circuit is additionally provided between resistance, wherein between the output end and the first end of divider resistance of PWM voltage modulated modules also
It is in series with inductance L；Between inductance L and the first end of divider resistance Rf, it is also associated with the one end capacitance C, capacitance C connection partial pressure electricity
The first end of Rf is hindered, the other end is grounded GND.Since to avoid electric current on USB charging circuits instantaneous for the presence of inductance L and capacitance C
It increases or reduces or the impact for the external equipment that USB interface is connected that disappears.
In addition, the stability of the voltage for the further energization pins output for ensureing USB interface, in PWM voltage modulateds
It is also associated with zener diode D between the output end and inductance L of module 21；The cathode of zener diode D connects PWM voltage modulateds
The output end of module, plus earth GND.Wherein, the pressure voltage of zener diode D can be slightly larger than the maximum that certification rule requires
Voltage value, zener diode D punctures and is connected over the ground after more than the maximum voltage value, and too high voltages is avoided to cause external equipment
Damage.
In addition, the embodiment of the present invention also provides a kind of feed-back regulatory mechanism, wherein the USB charging circuits further include output
Voltage detecting circuit 26, output voltage detecting circuit 26 include first resistor R1, second resistance R2, the first end of first resistor R1
Connect the energization pins of USB interface, the first end of the second end connection second resistance R2 of first resistor R2, the of second resistance R2
Two ends are grounded GND；The second modulus that the second end of first resistor R1 is also connected with the second analog-to-digital conversion port AD2, CPU of CPU turns
Partial pressures of the port AD2 for detecting first resistor R1 is changed, to determine it is pre- whether the voltage of the energization pins output of USB interface meets
If condition.The preset condition can be voltage range as defined in certification rule, and when being unsatisfactory for the preset condition, CPU can be with
Pwm control signal is readjusted in conjunction with the sampled voltage of Rf, it is final so that the voltage satisfaction of the energization pins output of USB interface is recognized
Card rule.
In addition, voltage detection unit 23 may include a signal amplification circuit, specifically as shown in Fig. 2, being put including signal
Big device, the wherein first end of forward end (+) connection divider resistance Rf of signal amplifier, the backward end (-) of signal amplifier connect
The second end of divider resistance Rf is connect, the output end of signal amplifier connects CPU, the wherein reverse side and output end of signal amplifier
Between be in series with feedback resistance R105.
The above description is merely a specific embodiment, but scope of protection of the present invention is not limited thereto, any
Those familiar with the art in the technical scope disclosed by the present invention, can easily think of the change or the replacement, and should all contain
Lid is within protection scope of the present invention.Therefore, protection scope of the present invention should be based on the protection scope of the described claims.
Claims (6)
1. a kind of USB interface charging circuit, which is characterized in that including：
Divider resistance, the divider resistance first end are connected to power input, the partial pressure electricity by PWM voltage modulated modules
The second end of resistance is connected to the energization pins of USB interface, and the charging current that power supply provides flows through the divider resistance to the confession
Electric pin, with the charging external equipment connected to the USB interface；
Voltage detection unit, the first input end of the voltage detection unit connect the first end of the divider resistance, the electricity
Second input terminal of pressure detection unit connects the second end of the divider resistance, the output end and CPU of the voltage detection unit
Connection, the partial pressure value for detecting and amplifying the divider resistance generates sampled voltage, and the sampled voltage is sent to
CPU；
The output end of the first analog-to-digital conversion end connection voltage detection unit of CPU, the CPU is for receiving the voltage detecting list
The sampled voltage that member is sent controls according to the sampled voltage and generates pwm control signal, and by the ends PWM by the PWM
Control signal is sent to PWM voltage modulated modules, and the pwm control signal has predetermined duty ratio；
The control terminal of PWM voltage modulated modules, the PWM voltage modulateds module connects the ends PWM of the CPU, the PWM voltages
The input terminal of modulation module is connect with power input, output end and the divider resistance of the PWM voltage modulateds module
First end connects；For receiving the pwm control signal, its input terminal and output end are adjusted according to the pwm control signal
The duty ratio of turn-on time, to adjust the voltage of the energization pins output of the USB interface.
2. USB interface charging circuit according to claim 1, which is characterized in that the PWM voltage modulateds module includes the
One switching transistor and second switch triode；
The base stage of the first switch triode is connect with the CPU, emitter ground connection, collector and three pole of the second switch
The base stage of pipe connects；
The emitter of the second switch triode is connect with power input, and the first end of collector and the divider resistance connects
It connects.
3. USB interface charging circuit according to claim 1, which is characterized in that in the defeated of the PWM voltage modulateds module
It is also in series with inductance between outlet and the first end of the divider resistance；
Between the inductance and the first end of the divider resistance, it is also associated with capacitance, described point of capacitance one end connection
The first end of piezoresistance, other end ground connection.
4. USB interface charging circuit according to claim 3, which is characterized in that in the defeated of the PWM voltage modulateds module
It is also associated with zener diode between outlet and the inductance；
The cathode of the zener diode connects the output end of the PWM voltage modulateds module, plus earth.
5. USB interface charging circuit according to claim 1, which is characterized in that further include output voltage detecting circuit, institute
It includes first resistor, second resistance to state output voltage detecting circuit, and the first end of the first resistor connects the USB interface
Energization pins, the second end of the first resistor connect the first end of the second resistance, the second termination of the second resistance
Ground；
The second end of the wherein described first resistor is also connected with the second analog-to-digital conversion port of the CPU, the second modulus of the CPU
Conversion port is used to detect the partial pressure of the first resistor, and whether the voltage exported with the energization pins of the determination USB interface
Meet preset condition.
6. USB interface charging circuit according to claim 1, which is characterized in that voltage detection unit includes signal amplification
Device, the wherein first end of forward end connection divider resistance of signal amplifier, the backward end of signal amplifier connect divider resistance
Second end, the output end of signal amplifier connects CPU, is wherein in series between the reverse side and output end of signal amplifier anti-
Feed resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710131213.1A CN108574310A (en) | 2017-03-07 | 2017-03-07 | A kind of USB interface charging circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710131213.1A CN108574310A (en) | 2017-03-07 | 2017-03-07 | A kind of USB interface charging circuit |
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| Publication Number | Publication Date |
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| CN108574310A true CN108574310A (en) | 2018-09-25 |
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ID=63577405
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710131213.1A Pending CN108574310A (en) | 2017-03-07 | 2017-03-07 | A kind of USB interface charging circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109391007A (en) * | 2018-11-16 | 2019-02-26 | 北汽福田汽车股份有限公司 | Vehicle, charging unit |
| CN111864818A (en) * | 2019-04-28 | 2020-10-30 | Oppo广东移动通信有限公司 | Charging control circuit, charging control method, charging receiving circuit and split type electronic equipment |
| CN113629801A (en) * | 2021-07-15 | 2021-11-09 | 深圳天德钰科技股份有限公司 | Power supply device |
| CN113687679A (en) * | 2021-07-06 | 2021-11-23 | 逸超科技(北京)有限公司 | Cable voltage drop compensation circuit and ultrasonic imaging system |
| CN114928244A (en) * | 2022-06-29 | 2022-08-19 | 深圳市微源半导体股份有限公司 | Line loss compensation correction method and circuit based on output current |
-
2017
- 2017-03-07 CN CN201710131213.1A patent/CN108574310A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109391007A (en) * | 2018-11-16 | 2019-02-26 | 北汽福田汽车股份有限公司 | Vehicle, charging unit |
| CN111864818A (en) * | 2019-04-28 | 2020-10-30 | Oppo广东移动通信有限公司 | Charging control circuit, charging control method, charging receiving circuit and split type electronic equipment |
| CN113687679A (en) * | 2021-07-06 | 2021-11-23 | 逸超科技(北京)有限公司 | Cable voltage drop compensation circuit and ultrasonic imaging system |
| CN113629801A (en) * | 2021-07-15 | 2021-11-09 | 深圳天德钰科技股份有限公司 | Power supply device |
| CN114928244A (en) * | 2022-06-29 | 2022-08-19 | 深圳市微源半导体股份有限公司 | Line loss compensation correction method and circuit based on output current |
| CN114928244B (en) * | 2022-06-29 | 2023-03-10 | 深圳市微源半导体股份有限公司 | Line loss compensation correction method and circuit based on output current |
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