CN208078898U - A kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs - Google Patents
A kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs Download PDFInfo
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- CN208078898U CN208078898U CN201820517991.4U CN201820517991U CN208078898U CN 208078898 U CN208078898 U CN 208078898U CN 201820517991 U CN201820517991 U CN 201820517991U CN 208078898 U CN208078898 U CN 208078898U
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Abstract
The utility model is related to a kind of pulsewidth Linear voltage-adjusting circuits applied to DC/DC outputs, the circuit includes PWM controller, pulse wide voltage-regulation sub-circuit and DC/DC Translator subcircuits, input of the adjustable square-wave signal of PWM controller output duty cycle as pulse wide voltage-regulation sub-circuit, the feedback signal of the pulse wide voltage-regulation sub-circuit is as the feed back input as DC/DC converters in DC/DC Translator subcircuits.Compared with prior art, the utility model has many advantages, such as to export variable voltage, linear voltage regulation in real time.
Description
Technical field
The utility model is related to DC/DC circuit fields, are linearly adjusted more particularly, to a kind of pulsewidth applied to DC/DC outputs
Volt circuit.
Background technology
DC/DC conversion circuits are a kind of turns that high pressure (low pressure) DC power supply is transformed to low pressure (high pressure) DC power supply
Circuit is changed, the output voltage after transformation can be fixed voltage value, can also be variable voltage value.For exporting variable voltage
Value, traditional way are to carry out mechanical adjustment using potentiometer, and such mode can not be efficiently applied to output voltage and become in real time
In the scene of change.
Utility model content
The purpose of this utility model is exactly to be provided a kind of applied to DC/ to overcome the problems of the above-mentioned prior art
The pulsewidth Linear voltage-adjusting circuit of DC outputs.
The purpose of this utility model can be achieved through the following technical solutions：
A kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs, the circuit include PWM controller, pulse wide voltage-regulation
Circuit and DC/DC Translator subcircuits, the adjustable square-wave signal of PWM controller output duty cycle is as pulse wide voltage-regulation
The feedback signal of the input of circuit, the pulse wide voltage-regulation sub-circuit is used as DC/DC to convert as in DC/DC Translator subcircuits
The feed back input of device.
The pulse wide voltage-regulation sub-circuit include first resistor, second resistance, 3rd resistor, the 4th resistance, the 5th resistance,
6th resistance and the first capacitance, the output end of the PWM controller, the 4th resistance, 3rd resistor, DC/DC converters it is anti-
Feedback input terminal is sequentially connected, and the output end of the PWM controller is connect by the 5th resistance with electric power network, and the described the 6th
Resistance one end is connected between the 4th resistance and 3rd resistor, and other end ground connection, the first described capacitance one end is connected to the 4th
Between resistance and 3rd resistor, other end ground connection, described first resistor one end is connect with 3rd resistor, the other end and output electricity
Press bond, described second resistance one end are connect with 3rd resistor, other end ground connection.
The DC/DC Translator subcircuits further include the first inductance and the second capacitance, and the DC/DC converters are opened
OFF signal output end is connect by the first inductance with output voltage terminal, the second described capacitance one end and the first inductance connection, separately
One end is grounded.
The second resistance is to place resistance or potentiometer.
The pulsewidth Linear voltage-adjusting circuit is to realize linear voltage regulation function, the linear voltage regulation formula：
Vout=Vmax-(Vmax-Vmin)*Duty
Wherein, VmaxFor exportable maximum voltage, VminFor exportable minimum voltage, VoutFor actual output voltage,
Duty is the duty ratio of pwm input signal.
The resistance value of the second resistance is less than 20K Ω, and the resistance value of the 6th resistance is less than 10K Ω, the electricity
The voltage value of source network is 1.8V or 3.3V, and the feedback voltage level of the DC/DC converters is 0.6V.
Compared with prior art, the utility model has the following advantages：
The utility model realizes DC/DC output voltages continuous variable in a certain range by PWM pulse-width regulateds, practical to survey
Test result and agreement with theoretical calculation can realize the pressure regulation of different range according to variation of parameter, realize potentiometer machinery tune
Section can not export the function of variable voltage in real time.
Description of the drawings
Fig. 1 is the topological schematic diagram of pulse wide voltage-regulation sub-circuit.
Fig. 2 is the circuit diagram of DC/DC Translator subcircuits.
Fig. 3 is DC/DC maximum voltage output equivalent circuits.
Fig. 4 a are the disconnected equivalent circuit of current source void.
Fig. 4 b are the empty short equivalent circuit of voltage source.
Fig. 5 is up/down pull-up resistor equivalent circuit inside PWM controller.
Fig. 6 is single order RC filter circuits.
Specific implementation mode
The utility model is described in detail in the following with reference to the drawings and specific embodiments.
Embodiment
The utility model provides a kind of easy hardware circuit topology, realizes output voltage certain based on pulse-width regulated
Continuous variable in range solves the drawbacks of using potentiometer mechanical adjustment, such as Fig. 1 institutes with extremely low cost and extremely simple structure
To show, the hardware circuit topology of pulse wide voltage-regulation sub-circuit shown in the utility model is as follows, including six resistance and a capacitance, six
A resistance is that R1, R2, R3, R4, R5, R6, one capacitances are C1 respectively；Include additionally four road interfaces, is control where PWM respectively
The electric power network VDDIO of device power domain processed, input signal PWM, output voltage DC/DC_out and feedback network DC/DC_FB；
Input end signal is pwm signal (PWM：Pulsewidth modulation), pwm signal is exported by controller, is the square-wave signal of variable duty ratio；
Output end signal DC/DC_out is connected to the voltage output pin of DC/DC conversion chips, exports variable DC voltage；Feedback net
Network signal DC/DC_FB is connected to the Voltage Feedback pin of DC/DC conversion chips；VDDIO provides DC voltage, direct current for circuit
The selection of voltage level requires to set according to controller.
Fig. 2 is chip pin description and the peripheral applications circuit for the DC/DC Translator subcircuits that the utility model uses.
The pin 4 and pin 1 of common DC/DC converters (such as product SY8088 of silergy companies) are respectively control source pipe
Enable pin is usually connected by foot and enable pin with voltage input pin, is powered by external dc voltage DC/DC_in；It is common
The pins 3 of DC/DC converters be switching signal output pin, pass through and connect inductance L1 and capacitance C0 and realize DC voltage DC/
DC_out is exported, and pin 5 is the input pin of feedback signal DC/DC_FB, is connected to as feed back input in the junctions R1 and R2
Pin 5；Wherein, when R2 is to place resistance, then DC/DC_out outputs are fixed voltage；If R2 is replaced electricity using potentiometer
Resistance, variable voltage can be exported by mechanical adjustment potentiometer.
The circuit function of the utility model is as follows：
Functional relation as shown in Table 1, the utility model is realized changes voltage based on first-order linear described in the function
Output；Under the premise of two parameters of ceiling voltage during function is determined and minimum voltage, it can be realized by adjusting duty ratio
Variable output voltage values.When DC/DC pulse wide voltage-regulation circuits work, acquiescence output voltage is the Type values in table 1, passes through tune
The width of the square wave high level of PWM outputs, i.e. duty ratio are saved, realizes the variation of output voltage；When input square wave high level width
It is 100%, i.e., duty ratio is 100%, and output voltage is Vmin values in table 1 at this time；It is 0 when inputting square wave high level width, i.e.,
Duty ratio is 0%, and output voltage is Vmax values in table 1 at this time；Between input square wave high level duty ratio is 0% to 100%
Some value when, output voltage be table in functional relation；Two parameters of Max and Min in table 1 can be repaiied according to actual demand
Change.The utility model with Vmax=1.4V, Vmin=0.8V as actual verification circuit, substituted into equation can obtain it is new
Functional relation：
Vout=1.4- (1.4-0.8) * Duty；
1 output voltage functional relation table of table
Table 2A input parameter tables
Table 2B output parameter tables
Wherein, voltage unit V (volt), unit of resistance KOhm (kilohm), chronomere uS (microsecond), unit of capacity nF
(nano farad)；
Vout：The exportable virtual voltage of DC/DC pulse wide voltage-regulation circuits；
Vmax：The exportable maximum voltage of DC/DC pulse wide voltage-regulation circuits；
Vtype：The exportable reset default voltage of DC/DC pulse wide voltage-regulation circuits；
Vmin：The exportable minimum voltage of DC/DC pulse wide voltage-regulation circuits；
VDDIO：Controller power source domain VDDIO voltage values where PWM；
DC/DC_FB：DC/DC internal reference voltage values, common is 0.6V or 0.8V；
R2：Generally 200K ohm or less resistance；
R6：The generally following resistance of 10K ohmic resistances；The utility model is by taking 12KOhm as an example；
Up/down is drawn inside R5, PWM:It needs to export source chip requirement according to PWM；The utility model is by taking 60KOhm as an example；
Pressure regulation time t：Refer to after PWM duty cycle variation, output voltage reaches 99% time needed of target voltage values；
The utility model design principle is as follows：
In order to which Linear voltage-adjusting circuit described in equation Vout=Vmax- (Vmax-Vmin) * Duty, this reality may be implemented
Corresponding hardware circuit topology is proposed with novel, physical circuit is as shown in Fig. 1 dotted line frames；Each section is specific in circuit topology
The determination of parameter depends on given input parameter value, and output parameter value is calculated by input parameter value；Input parameter and defeated
Go out parameter and constructs final pulsewidth Linear voltage-adjusting circuit topology together；
Circuit input parameter：
VDDIO, the utility model can be 3.3V or other voltage values by taking 1.8V as an example；
The maximum voltage of DC/DC outputs, the utility model is by taking 1.4V as an example, and minimum voltage is by taking 0.8V as an example；
DC/DC_FB feedback voltage level Vfb, the utility model are with reference to (according to the DC/DC conversions actually selected with 0.6V
Depending on device requires)；
R2 resistances, the utility model is by taking 200KOhm as an example (according to the DC/DC converters requirement actually selected
It is fixed).
The specific calculating process of output parameter：
The parameters relationship required according to the DC/DC converter chips that the utility model uses calculates, it is known that R2 resistance values
200KOhm, can calculate R1 resistance values, and R1=(Vtype-Vfb)/(Vfb/R2)=(0.9-0.6)/(0.6/200K)=
100KOhm；
When DC/DC exports maximum voltage, PWM inputs are 0V, i.e. are equivalent to be grounded on the left of R4, as shown in Figure 3；Thus it counts
It calculates：(R3+R4//R6) (electric current for flowing through R1 is equal to equivalent resistance=100k/ ((1.4-0.6)/0.6)=75k of //R2
The total current of equivalent circuit below)；(R3+R4//R6)=1/ (1/75-1/200)=120k=R3；
When DC/DC exports minimum voltage, PWM inputs are VDDIO (the utility model is verified with VDDIO=1.8V)
DC voltage value flows through the electric current (0.6- of R2 at this point, electric current (the 0.8-0.6)/100k=2uA for flowing through R1 is calculated
0.0)/200k=3uA；Illustrate that also 1uA is the electric current for flowing through R3, left-to-right flow direction, I3=1uA；
Therefore when DC/DC exports minimum voltage, the absorption current source that an equivalent starting voltage is 0.6V on the right side of R3,
Electric current 1uA is absorbed, current source is equivalent to void in Thevenin's theorem and breaks, is equivalent to open a way on the right side of R3；Such as Fig. 4 a；It can obtain
1.8V/ (R4+R6) * R6=Vr6
VDDIO is as ideal voltage source, voltage source equivalent void short circuit in Thevenin's theorem, such as Fig. 4 b；Therefore equivalent
R4 left side grounds；Obtain Vr6=I3*R3 "/1000+0.6=0.72V
The equation that two kinds of equivalent circuits obtain passes through Vr6 equivalences：
1.8V/ (R4+R6) * R6=Vr6=I3*R3 "/1000+0.6=0.72V, obtain R4=1.5*R6=18KOhm；
R3=R3 "-R4//R6=120K-7.2K=112.8KOhm may further be acquired；
There are up/down pull-up resistors inside the controller of output pwm signal, as shown in figure 5, calculating R5 based on this；
Pull-up resistor configures：R5//Rpu=(1.8V-1.5V)/(0.6V/12k)=6k, can calculate R5=6.7kOhm；
Pull down resistor configures：Rpd//(R4+R6)=60k//30k=20k；Calculate R5=(1.8V-1.5V)/(1.5V/
20k)=4kOhm；
Rpu equivalent pull-up resistors inside device in order to control；Rpd equivalent pull down resistors inside device in order to control；
R4, R6 and C1 collectively constitute the RC first-order low-pass wave circuits described in Fig. 6, which realizes the square wave of input
Signal is converted into DC voltage, but there are time-delay characteristics for filter, and reaching target voltage values when directly resulting in each pressure regulation needs
The regular hour is wanted, the following equation of voltage characteristic of single order RC filtering：U0=Ui* (1-e^ (- t/rc)), pressure regulation timing definition are
Charging pressure-boosting can obtain e^ [- t/ (r*C1)]=1-0.99 to the 99% of target voltage, release t=4.6* (R4//
R6) * C1=330uS, calculating can obtain C1=9.96nF；E is the nature truth of a matter 2.71828 in formula；
R4//R6 indicates that resistance R4 and resistance R6 is in parallel, // for symbol in parallel, in text, elsewhere description is herewith；
Practical application circuit is built and verification result：
The pulse wide voltage-regulation circuit based on DC/DC, the DC/DC converter chips of selection are built according to the result of theoretical calculation
Feedback network DC/DC_FB be 0.6V；VDDIO uses 1.8V power voltage supplies；Up/down pull-up resistor resistance inside the controller of selection
Value is 60KOhm, this verification is configured using controller internal pull-up resistor；
The resistance and capacitance parameter value and practical common parameter value gone out due to theoretical calculation is not fully identical, actually answers
It in, is verified as close as reason calculated value, therefore as shown in table 3, actually uses R3 in parameter and use
118KOhm, R5 (configuration of controller internal pull-up resistor) use 6.8KOhm, C1 to use 10nF, remaining device parameters chooses and reason
It is consistent by calculated value；
Find out from 3 experimental result of table, actual test result and theoretical calculation are very close, and error is in 0.5%.
3 actual test result of table
Claims (5)
1. a kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs, which is characterized in that the circuit includes PWM controller, arteries and veins
Wide-voltage-regulation sub-circuit and DC/DC Translator subcircuits, the adjustable square-wave signal of PWM controller output duty cycle is as arteries and veins
The input of wide-voltage-regulation sub-circuit, the feedback signal of the pulse wide voltage-regulation sub-circuit is as conduct in DC/DC Translator subcircuits
The feed back input of DC/DC converters.
2. a kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs according to claim 1, which is characterized in that institute
The pulse wide voltage-regulation sub-circuit stated includes first resistor (R1), second resistance (R2), 3rd resistor (R3), the 4th resistance (R4),
Five resistance (R5), the 6th resistance (R6) and the first capacitance (C1), the output end of the PWM controller, the 4th resistance (R4),
Three resistance (R3), DC/DC converters feedback input end be sequentially connected, the output end of the PWM controller passes through the 5th electricity
Resistance (R5) is connect with electric power network (VDDIO), and the 6th described one end resistance (R6) is connected to the 4th resistance (R4) and third electricity
Between hindering (R3), other end ground connection, described one end the first capacitance (C1) is connected to the 4th resistance (R4) and 3rd resistor (R3)
Between, other end ground connection, first resistor one end (R1) is connect with 3rd resistor (R3), and the other end connects with output voltage terminal
It connects, second resistance one end (R2) is connect with 3rd resistor (R3), other end ground connection.
3. a kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs according to claim 2, which is characterized in that institute
The DC/DC Translator subcircuits stated further include the first inductance (L1) and the second capacitance (C0), the switch of the DC/DC converters
Signal output end is connect by the first inductance (L1) with output voltage terminal, described the second capacitance one end (C0) and the first inductance
(L1) it connects, other end ground connection.
4. a kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs according to claim 2, which is characterized in that institute
The second resistance (R2) stated is to place resistance or potentiometer.
5. a kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs according to claim 2, which is characterized in that institute
The resistance value for the second resistance (R2) stated is less than 20K Ω, and the resistance value of the 6th resistance (R6) is less than 10K Ω, the power supply
The voltage value of network (VDDIO) is 1.8V or 3.3V, and the feedback voltage level of the DC/DC converters is 0.6V.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820517991.4U CN208078898U (en) | 2018-04-12 | 2018-04-12 | A kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201820517991.4U CN208078898U (en) | 2018-04-12 | 2018-04-12 | A kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108400708A (en) * | 2018-04-12 | 2018-08-14 | 上海健康医学院 | A kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs |
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2018
- 2018-04-12 CN CN201820517991.4U patent/CN208078898U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108400708A (en) * | 2018-04-12 | 2018-08-14 | 上海健康医学院 | A kind of pulsewidth Linear voltage-adjusting circuit applied to DC/DC outputs |
| CN108400708B (en) * | 2018-04-12 | 2024-01-23 | 上海健康医学院 | Pulse width linear voltage regulating circuit applied to DC/DC output |
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| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20181109 Termination date: 20210412 |
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| CF01 | Termination of patent right due to non-payment of annual fee |