TW201134078A - Power supply device having an adjustable switching frequency - Google Patents

Abstract

A power supply device having an adjustable switching frequency includes a control circuit and a constant-slope oscillation unit. The control circuit is used to control switching frequencies of the power supply device. The constant-slope oscillation unit is provided in the control circuit. The constant-slope oscillation unit includes a voltage clamp circuit, a constant-slope current reference circuit and a frequency oscillator. The constant-slope current reference circuit is used to provide a pulse, which is adjusted according to changes of loads, so as to control switching frequencies of the power supply device.

Description

201134078 Sixth, the invention description: [Technical field of the invention], the invention side of the power supply for the adjustable switching words [previous technology], the biliary solution.

Generally speaking, 'Lion power supply _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The efficiency is mainly determined by; -i maximum power consumption 'its fineness is the conduction, consumption and marriage ^ - a consumption of mm' conduction loss is the main power of the power supply main power wire 'na miscellaneous will be the power supply The edge adjustment method may make the power supply improve the output efficiency. The metamorphosis of the sheep's meta-muTM controller is in the selection of its external related electronic changes, Wei. The city is not able to age under load conditions and its switching loss is low. Therefore, the output efficiency of the conditional two-supplier in light load is usually poor. η j7 HUAWEI Patent Publication No. 583821 "Pulse Width Modulation Controller for Power Conversion Cry" The invention patent reveals the switch between two light and no load pairs. [triP-Pdnt]^ The frequency modulation of the benefit is achieved by modulating the action point of the shock I and the right analogy. However, the PWM control of 帛583821 has the disadvantage of complicated frequency modulation. The invention patent of "with wear-stop time, 'work equipment and method" disclosed in No. 1251978 of the Ministry of Foreign Affairs, Rev.

Top World/P09061TWSTX 201134078 is applied to the power supply of the secondary side control n voltage waveform detector by more

Subsampling - the voltage signal of the Weier, and generating a voltage feedback signal and a discharge time signal; -f voltage loop error All [vdtagek) QP amplifier] amplifying the voltage feedback signal and generating a control signal; Time modulation 1 [ofMmemodulaton generates a discharge-current signal correspondingly according to the under-voltage signal; an oscillator generates a pulse signal according to the discharge current signal; [pulse signal], the pulse signal determines the cut-off time of the switching signal. A pulse width s-variant generates a switching signal according to the pulse signal and the standby signal, and the standby signal controls the cut-off time of the switching signal, and maintains A minimum switching frequency. However, the switching control device No. 1251978 also has the disadvantage of being complicated in frequency. Furthermore, the invention patent of the "Double Slope Adaptive Frequency Controller for Adjusting Power Conversion" of the Republic of China Patent Publication No. 1279987 discloses that a power converter adjusts its operating frequency according to the load state of the load device. The power converter converts the error voltage into a conversion circuit to control the charge and discharge current of a storage capacitor to control the voltage cycle length of the capacitor to achieve the purpose of controlling the gate pulse frequency. Furthermore, U.S. Patent No. 6,545,882, "PWM Controller having 〇ff_time modulation for power controller" discloses that a PWM controller is used to control a light load or no load. The power controller performs a cut-off time modulation, and forms a feedback voltage by using a discharge current of the saw controller of the PWM controller (saw_t〇〇th_signal generator). The sixth, 545, 882 performs the off-time modulation by comparing the feedback voltage with a threshold voltage. Furthermore, U.S. Patent No. 6,597,159 "PWM controller has frequency...

4 Top World/P09061TWSTX 201134078 rate variable power converter (Pulse width modu丨ation controller having

The frequency modulation for power converter] patent provides a pwM controller to reduce the frequency modulation at light or no load. The frequency modulation is modulated by adjusting the trip-point voltage of an oscillator. Furthermore, the "Adaptive dual_sl〇pe frequeney controller for adjusting power conversion" patent of U.S. Patent No. 7,049,801 discloses an adaptive dual-slope frequency controller (adaptive dual- Slope frequency controller〕

Used to regulate power conversion. A feedback voltage is used to control the charge/discharge current of the two pairs of storage capacitors of the controller, thereby controlling the voltage waveform of the capacitor. Although various methods have been disclosed in U.S. Patent Nos. 6,545,882, 6,597,159 and 7,049,8 G1, their potential need for further improvement. For example, improving the linearity of the oscillator frequency modulation and simplifying the architecture of its control circuit. There are 4, in order to meet the above requirements, the present invention provides an adjustable switchable electric power county device, which has a 眺 震 震 单元 , , , , , , , , , , , , ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' In order to appropriately reduce the switching loss of the power supply for the switching transistor of the county, the purpose of improving the output efficiency of the power supply device is achieved. [Summary of the Invention] (4) The purpose is to provide a kind of power supply that can be difficult to switch to use to modulate the electricity; the element 'and the fixed slope shock (4) should be installed in the device to achieve the upgrade Power supply order

Top World/P09061TWSTX 5 201134078 - a control circuit for controlling the switching frequency of the power supply skirt; and a fixed slope oscillating unit disposed in the control circuit; wherein the 岐 slope oscillating element comprises a _ circuit, Slope current reference and "frequency money device, and the rate of shock of the second load changes its trajectory wave' in order to rely on the remainder of the relay = frequency. The power supply device for switching the adjustable switching frequency of the further preferred embodiment of the present invention comprises: a control circuit; and a fixed-slope oscillating unit disposed in the control circuit; wherein the fixed-slope oscillating unit provides A pulse signal of a fixed duty cycle to control the switching frequency of the power supply device according to the load. ° [Embodiment]

The invention is described in detail with reference to the preferred embodiments of the invention, The power supply device of the adjustable switching frequency of the preferred embodiment of the present invention can be applied to various switching power supply devices or similar power supply devices to reduce the switching loss of the switching transistor during light load. However, it is not intended to limit the scope of application of the power supply device of the present invention. Figure 1 shows a schematic diagram of a control circuit that can be employed by a power supply unit. Referring to Fig. 1, the control circuit 1 of the power supply unit includes an oscillator 10, a comparator 11, an SR latch 12, and a plurality of switching transistors 13, which are appropriately electrically connected. The power supply device is a switched power supply, and the control structure of the remote control circuit 1 is a current mode PWM control method. Referring to Figure 1 again, the RC element is externally connected to the oscillating device 1 so that the oscillating device 10 generates a pulse of a fixed oscillating frequency. The oscillating frequency activates the SR latch 12 in a periodic startup manner, and the latch 12

6 Top World/P09061TWSTX 201134078 reset [reset] action is detected by the control circuit current (10)] The output of the comparator u sense locker 12 determines the f U decision. When Wei's conduction and deadlines reach a stable ratio [mail:], the power supply unit can supply a stable output. Referring to FIG. 1 again, the output of the SR locker 12 is determined to be a maximum on-time of the period [Μ-"115"]. So: : Work out the view crystal 13 enters at startup

(D) Figure H shows a schematic diagram of a control circuit using a power supply with adjustable switching frequency in accordance with a preferred embodiment of the present invention. Referring to FIG. 2, the power supply device inspection circuit 2 of the embodiment of the present invention includes a fixed slope, a comparator 2, an SR latch 22, and a plurality of switching transistors 23, which have appropriate electrical properties. connection. Referring again to FIGS. 1 and 2, in terms of the component structure, the comparator 1 of the first diagram, the SR latcher 12, and the switch transistor 13 correspond to the comparator 21 of the second diagram, and the SR lock. The detector 22 and the switching transistor 23, therefore, the related description of the first drawing can be incorporated by reference, and will not be described in detail herein. Stomach - Referring again to Fig. 2, the fixed-slope oscillating unit 2A includes a voltage clamping circuit 20a, a fixed-slope current reference circuit 2, and a frequency oscillating benefit 20c. The voltage clamping circuit 2A is connected to the fixed slope current reference circuit 2'b' to output a voltage to the fixed slope current reference circuit 2'b. In addition, the 戎 fixed slope current reference circuit 2 〇 b is connected to the frequency oscillator 2 〇 c to output a current signal to the frequency oscillator 2 〇 (^ Finally, a fixed noble period is provided via the frequency oscillator 20 c Figure 3 is a schematic diagram showing the use of a voltage clamping circuit for the control circuit of the preferred embodiment of the present invention. However, it is not intended to limit the scope of the present invention. Referring to Figure 3, the voltage clamping circuit 2〇 a contains two comparators CMP1, CMP2 and t Si

7 Top World/P09061TWSTX 201134078 j Turn off the transistors Ml, M2, M3' with appropriate electrical connections. The two comparator CMP CMP2 and the three-switch transistor Heb M2 'M3 clamp the output voltage VI of the voltage clamping circuit 20a between a first predetermined voltage and a second predetermined voltage VG. Referring again to FIG. 3, when the Vc〇mp voltage is higher than the first predetermined voltage VN, 'the comparator CMpi is outputted at a high level to turn on the switching transistor M1' and the voltage clamping circuit 2 is 〇a readout voltage νι is limited to the level VN; in contrast, when the Vcomp voltage is lower than the second predetermined voltage vg, the comparison S CMP2 is output to a high level to turn on the switching transistor M2, and • the voltage The output voltage VI of the clamping circuit 20a is limited to the level VG;

When the Vcomp voltage is between the first predetermined voltage w and the second predetermined voltage vg, the gate transistor M3 is turned on, and the voltage clamp circuit is applied with the output voltage vi equal to the Vcomp level. The voltage system circuit 2a can be used to set the input range to ensure that the electrical material is saturated with a new one. Figure 4 shows a schematic diagram of a control circuit using a fixed slope current reference circuit in the preferred embodiment of the present invention, but it is not intended to limit the scope of the present invention. Please refer to Figure 4 for the fixed slope current reference circuit. 2 includes an operational amplification state A, a transistor Mrd, an external resistor Rext, and a current mirror circuit (current-mirror drcuit) having an appropriate electrical connection, and the fixed slope current reference circuit 20b via the current mirror circuit Providing two reference currents. The current mirror circuit is composed of three transistors Μρι, Mp2, Mp3, and two transistors, Mn3, which are electrically connected. Please refer to Figures 3 and 4 for the pre-voltage clamp circuit. The output voltage VI (shown in FIG. 3) is output to the subsequent fixed-slope current reference circuit 20b. As shown in FIG. 4, in the fixed-slope current reference circuit 2〇b, the input voltage VI is subjected to the operation. The amplifier A1, the transistor and the external resistor Rext are converted into a current signal, and then the current signal is output to the current.

I ^ J

8 Top World/ΡΟ卯61TWSTX 201134078 Mirror circuit' and in the current mirror circuit proportionally generate two reference ohms to determine the on-time. The p-eye is tilted again as shown in Fig. 4. For example, when the two reference currents & and the ratio [Ip: In] are designed to be equal to [i: i], they provide a pulse of 5〇% of the on-time. When the two reference currents Ip, In are designed to []: 3], '3Ιρ=1Ιη' provides a pulse wave of 75% of the on time.

. Figure 5 is a schematic illustration of a control circuit employing a frequency oscillator in accordance with a preferred embodiment of the present invention, but is not intended to limit the scope of the invention. Referring to Fig. 5, the frequency oscillator 2〇c is composed of a comparator cMp3, four health switches P, fii, S1 and S2 and a charging capacitor Cs, which have appropriate electrical connections. The fixed-slope oscillating unit 2 can provide a pulse signal of a fixed duty cycle via the stimuli. In the frequency oscillator 2?c, when the initial value Out is equal to 0, the control switches S1 and Sp are turned on. At this time, the input of the comparator CMP3 is dedicated to VH, and the reference charge & simultaneously charges the charging capacitor Cs to the level VH. Referring again to Fig. 5, when the voltage Vcs of the charging circuit Cs is slightly higher than the level VH, the output level of the comparator CM?3 is inverted to (10) equal to 1. When Out is equal to 〗, the control switch is turned on by %. At this time, the potential of the input negative terminal of the comparator CMP3 is VL, and the potential is discharged from the reference In to the level VL. Referring again to FIG. 5, next, when the voltage Vcs of the charging capacitor & is slightly lower than the level VL, the output level of the comparator CMP3 is inverted to 〇ut equal to 〇. According to this periodic operation, the frequency oscillator 2c can generate a pulse signal ' and the period of the pulse can be derived by the following formulas [丨] to [3]. The present invention adopts the formulas [1] to [3] as follows:

Ton = Cs(VH-VL)/Ip π]

Toff = Cs(VH-VL)/In 〔 2] T = Ton+Toff=l/f [ 3] m

9 Top World/P09061TWSTX 201134078 FIG. 6 discloses a power supply device with adjustable switching frequency according to a preferred embodiment of the present invention, which uses a control circuit to display a waveform at each node [Vc〇mp, YU, 0^]. As shown, the control circuit of the preferred embodiment of the present invention has three stages in which the feedback voltage V_P is greater than VN, between VN and VG, and less than VG. In May, referring to Figure 6, when the feedback voltage Vc〇mp is greater than ^,

The charge and discharge time of Vcs will remain constant, so the frequency of 〇m is also fixed, as shown in the left part of Figure 6. When Vc〇mp is between and between,

The reference current of the charge and discharge of Vcs will also drop, so the ◦_frequency will also drop Ik' but the turn-through rate of S: will change the value, as shown in the middle part of the =. When VeQmp is smaller than VG, the female internal multi-test current is used, so that the frequency of (5) is limited, as shown in the right hand of Figure 6. The foregoing preferred embodiment of the canister is an example of a technique for performing a substantial equivalent modification and/or replacement of the scales. The scope of the invention must be regarded as the latter (4)

m

Top World/P09061TWSTX 201134078 [Simple description of the diagram] Figure 1: The power supply unit can be schematic diagram of the control circuit. Figure: Power supply arrangement for adjustable switching frequency in accordance with a preferred embodiment of the present invention. ^ Figure 3: A schematic diagram of a control circuit using a voltage clamp circuit in accordance with a preferred embodiment of the present invention. Power

BRIEF DESCRIPTION OF THE DRAWINGS The control circuit of the preferred embodiment of the present invention employs a fixed slope electrical b'L > Figure 5 is a schematic illustration of a control circuit in accordance with a preferred embodiment of the present invention. "Ding Nong 1 stealing Figure 6: The adjustable switching frequency of the preferred embodiment of the present invention... The waveform of the control circuit at each node is used. '", [Major component symbol description] 10 Oscillator 12 SR latch 20 fixed slope oscillating unit 20b fixed slope current reference circuit 22 SR latch 1 control circuit H comparator 13 switching transistor 2 control circuit 20a electric clamp circuit 20c frequency oscillator 21 comparator 23 switching transistor

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Claims (1)

201134078 VII. Patent application scope: 1. A power supply device capable of adjusting a switching frequency, comprising: a control circuit for controlling a switching frequency of the power supply device; and a fixed slope oscillating unit disposed at the control The fixed-slope oscillating unit includes a voltage clamping circuit, a fixed-slope current reference circuit, and a frequency oscillator, and the fixed-slope oscillating unit changes its output pulse wave according to the load, so as to rely on the negative power supply device Switch frequency. 2, according to the application of the general _ 丨 可 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻The off transistor rib clamps the output voltage of the voltage clamping circuit between a first predetermined voltage and a second predetermined voltage. 3. The power supply device of the adjustable switching frequency according to claim 1, wherein the fixed slope current reference circuit comprises an operational amplifier, an electrical body, an external resistor and a current mirror circuit, which have appropriate Electrically connected, and the 3 Hz fixed slope current reference circuit provides two reference currents via the current mirror circuit. 4. The power supply device of the adjustable switching frequency according to item 3 of the patent application scope, wherein the current mirror circuit is composed of three transistors and two transistors suitably electrically connected. 5. The power supply device of the adjustable switching frequency according to the first aspect of the patent scope, wherein the frequency oscillator is composed of a comparator, four control switches and a charging top W〇rld/P〇9〇61TWSTX 201134078 Electric power group, 'its financial mode' electrical connection' rated slope oscillation unit provides 1 duty cycle_pulse signal via this frequency oscillation n. 6 kinds of power supply devices with adjustable cutting rate, including a control circuit; and a fixed slope fresh element, which is set_control circuit; wherein the read rate oscillation unit provides a pulse signal for the duty cycle, so as to The load controls the switching frequency of the power supply device. 7. The power supply device of the adjustable switching frequency according to item 6 of the patent application scope has a surface-slope constant vibration element having a voltage clamp dying circuit, which comprises two comparators and a three-switch transistor, which have appropriate Electrically connected, the two comparators and the two switches are clamped between the first predetermined voltage and the second applied voltage. 8. The power supply device of the switchable word according to the application of the patent is turned over. The + fixed-slope unit has a fixed slope current reference circuit, which includes an operational amplifier, a transistor, an external resistor and a current. The mirror circuit 'has a suitable button connection, and the axis-slope cake reference circuit provides two reference currents via the current mirror circuit. 9. According to the application, the power supply device of the eight-story sculpt rate can be seen. The current mirror circuit consists of three transistors and two transistors. 10. According to the application of the _ _ 6 item of the power supply unit of the cut-off rate, where the gorge slope oscillating unit has a frequency oscillator, which is compared by a Top World/P〇9〇61TWSTX 13 201134078 The device is composed of four control switches and a charging capacitor, and has a suitable electrical connection. The fixed-slope oscillating unit provides a pulse signal of a fixed duty cycle via the frequency oscillator. t SI 14 Top World/P0906ITWSTX