CN1123111C - Switchable power unit capable of altering switching frequency with DC voltage - Google Patents
Switchable power unit capable of altering switching frequency with DC voltage Download PDFInfo
- Publication number
- CN1123111C CN1123111C CN 00100547 CN00100547A CN1123111C CN 1123111 C CN1123111 C CN 1123111C CN 00100547 CN00100547 CN 00100547 CN 00100547 A CN00100547 A CN 00100547A CN 1123111 C CN1123111 C CN 1123111C
- Authority
- CN
- China
- Prior art keywords
- switching
- voltage
- frequency
- capacitor
- resistor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000006243 chemical reaction Methods 0.000 claims abstract description 15
- 239000003990 capacitor Substances 0.000 claims description 31
- 238000001514 detection method Methods 0.000 claims description 21
- 238000010586 diagram Methods 0.000 description 6
- 230000000737 periodic effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000009123 feedback regulation Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
Images
Landscapes
- Dc-Dc Converters (AREA)
Abstract
The present invention relates to an exchange type power unit capable of altering a switching frequency along with a DC voltage, which comprises a switch, a switching control device, a frequency selective device and an energy conversion device, wherein the switch is used for receiving a direct current voltage, and an output end of the switch is connected with the energy conversion device. The switching control device is respectively connected with a control end of the switch and the frequency selective device. A DC input voltage is output to the frequency selective device, the switch corresponding to a switching signal carries out conduction or broken switching, and a switching waveform voltage is output. The power unit can be used for adjusting the frequency of the switching signal according to the magnitude of an input DC voltage, so the voltage conversion efficiency is enhanced, and the power consumption is reduced.
Description
The present invention relates to a power supply device, and more particularly, to a switching power supply device capable of changing a switching frequency with a dc voltage.
Fig. 1 shows a block diagram of a conventional switching power supply, in which a feedback regulation control circuit for outputting voltage is omitted for simplicity.
As shown in fig. 1, the conventional switching power supply apparatus 1 mainly includes the following units. A switch 10, for example, formed by an NMOS transistor, receives a DC input voltage Vin. The dc input voltage Vin is supplied by a battery device or an ac input voltage (e.g. commercial power) is converted into a dc voltage through a rectifying device. For example, in a notebook computer, if a battery device is used, the dc input voltage is 10V, and if the battery device is used, the dc input voltage is 22V after rectification.
A switching control device 20 for outputting a periodic switching signal Vs to drive the switch 10 to perform the switching operation of on or off. The switch 10 is caused to output a switching waveform voltage Vx. The switching control device 20 generally uses a pulse modulation control device (PWM), and the frequency of the switching signal Vs is determined by the values of the resistor RT and the capacitor CT.
An energy conversion device 30, here a network of diodes, inductors and capacitors, is used to convert the switched waveform voltage Vx to a dc output voltage Vout.
Currently, a dc-dc switching power supply apparatus is used, for example, as shown in fig. 1, since the switching control switch 20 is configured with a fixed capacitor CT and a resistor RT; therefore, when the dc input voltage Vin changes, the frequency (or period) of the switching signal Vs is still fixed.
As shown in fig. 2A to 2C, the graphs show the corresponding changes of the duty cycles (e.g., 50%, 30%, 10%, respectively) of the switching signal Vs and the corresponding switching waveform voltage Vx output by the switch 10 when the dc input voltage (Vin is 10, 15, 20V) is different. The DC output voltage of the power supply device is adjusted to a specific level. Therefore, when the dc input voltage Vin becomes larger, the switching control device 20 is driven by the feedback control of the dc output voltage Vout, so that the duty cycle of the switching signal Vs is also reduced; on the contrary, when the dc input voltage Vin is smaller, the switching control device 20 is driven to increase the duty cycle of the switching signal Vs, so that the power supply device can output a dc voltage with a specific level.
As can be seen from fig. 2A to 2C, the diagonal areas (P1 to P3) of the switching waveform voltage Vx correspond to the energies to be converted into the dc output voltage Vout, respectively, and the energies P1 to P3 are theoretically equal. If the switch 10 is an ideal device and does not consume energy (i.e., does not conduct current at the same time) during the on/off switching, the above-mentioned P1-P3 can be converted into the dc output voltage Vout theoretically. However, in practice, the switch 20 loses energy during switching (on/off), that is, during both the rising period tr (rise time) and the falling period tf (fall time) of the switching waveform voltage Vx. The energy lost Pd is approximately proportional to tr × f (or tf × f), where f represents the frequency of the switching signal Vs.
When the dc input voltage is high (for example, Vin 20V), the required rise (fall) time is quite long because the duty cycle of the switching signal Vs is very short; therefore, the proportion of the energy consumed in the predetermined conversion energy P3 is much larger than that when the dc input voltage is low, and the reactive loss reduces the conversion efficiency of the power supply apparatus.
Therefore, in view of the above-described disadvantage, if the frequency of the switching signal can be automatically reduced when the dc input voltage is high, the power loss can be reduced. The energy Pd consumed by the switch 20 during each switching operation is approximately proportional to tr × f, so that the frequency of the switching signal is reduced, and the power consumption during all switching operations can be greatly reduced.
The present invention provides a switching power supply device, which can adjust the frequency of the switching signal according to the change of the input DC voltage, so as to achieve the purpose of reducing unnecessary power loss and improving the conversion efficiency.
The invention adopts the following measures to achieve the aim:
the switching power supply device of the present invention includes: a switch, for example, formed by a power transistor, for receiving a dc input voltage, and switching on or off in response to a switching signal to output a switching waveform voltage; a switching control device, such as a pulse modulation control device, for outputting the switching signal; a frequency selection device for driving the switching control device to change the frequency of the switching signal by detecting the magnitude of the DC input voltage; and an energy conversion device for converting the switching waveform voltage into a DC output voltage.
The invention adopts the following specific structure:
the invention relates to a switching power supply device capable of changing switching frequency along with direct current voltage, which comprises: a switch, a switching control device, a frequency selection device and an energy conversion device;
the switch is used for receiving a direct current input voltage, and the output end of the switch is connected with the energy conversion device; the switching control device is respectively connected with the control end of the switch and the frequency selection device; inputting a direct current voltage and outputting the direct current voltage to a frequency selection device;
the switch is controlled to switch on or off corresponding to a switching signal, and a switching waveform voltage is output;
the switching control device is used for outputting the switching signal;
the frequency selection device drives the switching control device to change the frequency of the switching signal by detecting the magnitude of the direct current input voltage;
the energy conversion device is used for converting the switching waveform voltage into a direct current output voltage.
The switching control device is provided with a frequency adjusting input interface, and the frequency of the switching signal is changed by using a resistor and capacitor combination connected with the frequency adjusting input interface.
Wherein the frequency selection means comprises: a voltage detection unit, a resistor switching device, at least one capacitor and at least two resistors; the resistor switching device connects the resistor selection combination to the frequency adjustment input interface according to the detection result of the voltage detection unit.
Wherein the frequency selection means comprises: a voltage detection unit, a capacitor switching device, at least one resistor and at least one capacitor; the capacitor switching device connects the capacitor selection combination to the frequency adjustment input interface according to the detection result of the voltage detection unit.
Wherein, the frequency selection device comprises: a voltage detection unit, an impedance switching device, at least one resistor, and at least one capacitor; the impedance switching device selects the resistor and the plurality of capacitor selection combinations according to the detection result of the voltage detection unit and is respectively connected to the frequency adjustment input interface.
Wherein the switching control device is a pulse modulation control device.
Wherein the switch is a power transistor.
The specific structural features of the present invention are described in detail below with reference to the accompanying drawings and examples:
brief description of the drawings:
FIG. 1: a circuit block diagram of a conventional switching power supply device;
fig. 2A to 2C: when different direct current input voltages are applied, a corresponding change schematic diagram of a switching signal working period and a schematic diagram of corresponding switching waveform voltage output by a switch are shown;
FIG. 3: the circuit block diagram of the embodiment of the invention;
FIG. 4A: in the embodiment of the invention, the direct current input voltage has high voltage, and when the frequency of the switching signal is not changed, the waveform of the switching signal and the waveform of the switching waveform voltage are schematically shown;
FIG. 4B: in the embodiment of the invention, when the direct current input voltage has high voltage and the frequency of the switching signal is reduced to one half, the waveform of the switching signal and the waveform of the switching waveform voltage are schematically shown.
As shown in fig. 3, which is a circuit block diagram of an embodiment of the present invention, the feedback regulator control circuit for the output voltage is omitted in the figure for simplicity. The switching power supply device of the present invention can adjust the frequency of the switching signal according to the change of the input dc voltage, and includes the following units:
a switch 10, for example, formed by an NMOS power transistor, receives a dc input voltage Vin. The dc input voltage Vin is provided by a battery supply device or is converted into a dc voltage by a rectifying device. A switching control device 20, for example, a pulse modulation control device, is used to output a periodic switching signal Vs to drive the switch 10 to perform the on/off switching operation. Causing the switch 10 to output a switching waveform voltage Vx. In this embodiment, the switching control device 20 has a frequency adjustment input interface that includes: a frequency-adjusting capacitor input FC, fixedly coupled to a capacitor CT; and a frequency adjusting resistor input terminal FR.
An energy conversion device 30, which may be a network such as a network of diodes, inductors and capacitors (although the invention is not limited to such a network), is used to convert the switching waveform voltage Vx into a dc output voltage Vout.
A frequency selection device 40 comprising: a voltage detecting unit 40 a; a resistor (impedance) switching device 40 b; and a plurality of resistors (R1-R4). The voltage detecting unit 40a may be a network (not shown) composed of resistors to detect and sample the dc input voltage. According to the sampled value of the dc input voltage Vin, the comparators OP 1-OP 3 in the resistor (impedance) switching device 40b selectively turn on the transistors Q1-Q3, respectively, and selectively combine the resistors to connect to the frequency adjustment resistor input terminal FR of the switching control device 20, so as to drive the switching control device 20 to output the switching signal Vs with different frequencies.
For example, when Vin is 10V, the output of OP1 to OP3 turns on all of the transistors Q1 to Q3, so that the frequency adjustment resistor input FR of the switching control device 20 is connected to only the parallel combination of the four resistors R1 to R4, and the frequency of the output switching signal Vs is fs. When 10V < Vin is 15V, the output of OP 1-OP 2 turns on all of the transistors Q1-Q2, so the frequency adjustment resistor input FR of the switching control device 20 is connected to a parallel combination of three resistors (R1, R2 and R4), and the output switching signal Vs has a frequency of fs/2, for example. When 15V < Vin is 20V, the output of OP1 turns on the transistor Q1, so the frequency adjustment resistor input FR of the switching control device 20 is connected to the parallel combination of two resistors (R1 and R4), and the output switching signal Vs has a frequency of fs/3, for example. When Vin > 20V, the transistors Q1 to Q3 are not turned on by the outputs of OP1 to OP3, so the frequency adjustment resistor input terminal FR of the switching control device 20 is connected to only the resistor R4, and the output switching signal Vs has a frequency of fs/4, for example.
As can be seen from the above, if the value of the dc input voltage increases (e.g. from 10V to 22V), the switching signal Vs decreases (from fs to fs/4).
In this embodiment, the connection combination of the resistors of the frequency adjustment resistor input terminal FR is changed to adjust the frequency of the switching signal. However, the present invention is not limited to this, and the purpose of adjusting the frequency of the switching signal can also be achieved by connecting one fixed resistor to the frequency adjustment resistor input terminal FR, and then connecting a plurality of capacitors to the frequency adjustment capacitor input terminal FC by using the resistance switching device 40 b.
Of course, the present invention can also use the resistance switching device 40b to selectively combine a plurality of capacitors and resistors and then connect the capacitors and resistors to the frequency adjustment capacitor input FC and the frequency adjustment resistor input FR, respectively, so as to achieve the purpose of adjusting the frequency of the switching signal.
If the power supply is designed to change the frequency of the switching signal from the original frequency fo (10% of the period T) to the frequency fo/2 (10% of the period 2T) when the dc input voltage Vin is 20V. When the dc input voltage Vin is 20V and the switching signal still maintains the fixed frequency fo, the waveforms of the switching signal Vs and the switching waveform Vx are as shown in fig. 4A. When the dc input voltage Vin is 20V and the frequency of the switching signal is fo/2, the waveform of the switching signal Vs and the waveform of the switching signal Vx are as shown in fig. 4B.
As can be seen from fig. 4A and 4B, in the same time period (2T), the energy of the Vx voltage in fig. 4A converted into the dc output voltage Vout is the area Px11 plus Px12, while the energy of the Vx voltage in fig. 4B converted into the dc output voltage Vout is the area Px20, which are equal in the case where the switch 10 is not lossy. For the quantity Px20, the energy loss in the rise and fall times is significantly less than the energy loss in the rise and fall times of Px20, Px11 and Px12, respectively. Also, the energy loss in the rise and fall times shown in fig. 4A is 2 times greater than that in fig. 4B during 2T, since Px12 has extra energy consumption. Therefore, when the DC input voltage has high voltage, the invention automatically reduces the frequency of the switching signal, can indeed improve the conversion efficiency of the voltage and can reduce the energy loss.
The above description is provided for the purpose of illustrating the structural features of the present invention by way of example and is not intended to limit the scope of the present invention.
Claims (7)
1. A switching power supply apparatus capable of changing a switching frequency with a dc voltage, comprising: the energy conversion device is used for converting the switching waveform voltage into a direct current output voltage;
it is characterized in that the device also comprises a frequency selection device, wherein:
the output end of the switch is connected with the energy conversion device; the switching control device is respectively connected with the control end of the switch and the frequency selection device; inputting a direct current voltage and outputting the direct current voltage to a frequency selection device;
the switch is controlled to switch on or off corresponding to a switching signal, and a switching waveform voltage is output;
the frequency selection device drives the switching control device to change the frequency of the switching signal by detecting the magnitude of the direct current input voltage.
2. The power supply device according to claim 1, wherein the switching control device has a frequency adjustment input interface, and a resistor and a capacitor combination connected by the frequency adjustment input interface are used to change the frequency of the switching signal.
3. The power supply device according to claim 1, wherein the frequency selection device comprises: a voltage detection unit, a resistor switching device, at least one capacitor and at least two resistors; the voltage detection unit is respectively connected with a direct-current voltage input end and a resistor switching device, and the resistor switching device is connected with the resistor; wherein,
the resistor switching device connects the resistor selection combination to the frequency adjustment input interface according to the detection result of the voltage detection unit.
4. The power supply device according to claim 1, wherein the frequency selection device comprises: a voltage detection unit, a capacitor switching device, at least one resistor and at least one capacitor; the voltage detection unit is respectively connected with the direct-current voltage input end and the capacitor switching device, and the capacitor switching device is connected with the capacitor; wherein,
the capacitor switching device connects the capacitor selection combination to the frequency adjustment input interface according to the detection result of the voltage detection unit.
5. The power supply device according to claim 1, wherein the frequency selection device comprises: a voltage detection unit, an impedance switching device, at least one resistor, and at least one capacitor; the voltage detection unit is respectively connected with a direct-current voltage input end and an impedance switching device, and the impedance switching device is connected with the resistor and the capacitor; wherein,
the impedance switching device selects the resistor and the plurality of capacitor selection combinations according to the detection result of the voltage detection unit and is respectively connected to the frequency adjustment input interface.
6. The power supply device according to claim 1, wherein the switching control device is a pulse modulation control device.
7. The power supply device according to claim 1, wherein the switch is a power transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00100547 CN1123111C (en) | 2000-01-21 | 2000-01-21 | Switchable power unit capable of altering switching frequency with DC voltage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00100547 CN1123111C (en) | 2000-01-21 | 2000-01-21 | Switchable power unit capable of altering switching frequency with DC voltage |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1307395A CN1307395A (en) | 2001-08-08 |
| CN1123111C true CN1123111C (en) | 2003-10-01 |
Family
ID=4575520
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 00100547 Expired - Fee Related CN1123111C (en) | 2000-01-21 | 2000-01-21 | Switchable power unit capable of altering switching frequency with DC voltage |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1123111C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100336250C (en) * | 2002-08-30 | 2007-09-05 | 东芝电池株式会社 | Nickel based compound positive electrode material primary cell |
| CN100454732C (en) * | 2006-05-23 | 2009-01-21 | 广州电器科学研究院 | High accuracy high power constant current source and its realizing method |
| KR100952834B1 (en) * | 2008-08-06 | 2010-04-15 | 삼성모바일디스플레이주식회사 | Dc-dc converter and organic light emitting display using the same |
| CN103138571A (en) * | 2011-11-30 | 2013-06-05 | Ge医疗系统环球技术有限公司 | Power source circuit and portable ultrasonic testing device including the same |
-
2000
- 2000-01-21 CN CN 00100547 patent/CN1123111C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1307395A (en) | 2001-08-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102810984B (en) | Switching power circuit | |
| US6507504B2 (en) | Method of controlling DC/DC converter for reducing power consumption | |
| US20070018617A1 (en) | Current resonance type DC/DC converter capable of decreasing losses on on-load and a light load | |
| CN1849742A (en) | PFC-PWM controller having a power saving means | |
| CN1729722A (en) | Supply assembly for a LED lighting module | |
| CN102223747A (en) | PWM dimming LED driver and driving method thereof | |
| CN110445363B (en) | High-power pulse load power supply for inhibiting bus current peak | |
| CN110808681B (en) | Passive PFC resonant converter and control method thereof | |
| US7629779B2 (en) | Multiple output multiple topology voltage converter | |
| US6169392B1 (en) | DC-DC converter circuit | |
| CN1908740A (en) | Converter controller having feedforward compensation, converting system and method for controlling same | |
| JPH08289535A (en) | Dc-dc converter | |
| CN1819423A (en) | Switching regulator control circuit and switching regulator | |
| CN1123111C (en) | Switchable power unit capable of altering switching frequency with DC voltage | |
| CN1183651C (en) | Multiple output DC-DC converter and electronic device using said converter | |
| CN116260320B (en) | Switch circuit control method, switch circuit control chip and switch circuit | |
| CN110460237B (en) | Control method and device for PCCM Boost converter | |
| CN1294774A (en) | Switching power supply | |
| CN107742972B (en) | Continuous conduction mode double hysteresis pulse sequence control method and device thereof | |
| CN107769606B (en) | Capacitive current double-frequency pulse sequence control method and device thereof | |
| CN209806133U (en) | High-efficiency linear LED driving circuit | |
| CN112803744A (en) | Low-power-consumption power supply start control device and method and power supply equipment | |
| JPH10323027A (en) | Power supply circuit | |
| CN111293879A (en) | Driving method and device of current mode charge pump | |
| CN2828860Y (en) | Switch controller with feedback compensation and conversion system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20031001 Termination date: 20120121 |