TWI399037B - Ramp generator capable of stabilizing modulator gain, power converting system, and method thereof - Google Patents
Ramp generator capable of stabilizing modulator gain, power converting system, and method thereof Download PDFInfo
- Publication number
- TWI399037B TWI399037B TW98120843A TW98120843A TWI399037B TW I399037 B TWI399037 B TW I399037B TW 98120843 A TW98120843 A TW 98120843A TW 98120843 A TW98120843 A TW 98120843A TW I399037 B TWI399037 B TW I399037B
- Authority
- TW
- Taiwan
- Prior art keywords
- voltage
- ramp
- current
- input
- source
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims description 8
- 230000000087 stabilizing effect Effects 0.000 title claims description 4
- 239000003990 capacitor Substances 0.000 claims description 21
- 230000000153 supplemental effect Effects 0.000 claims description 21
- 238000007599 discharging Methods 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 239000013589 supplement Substances 0.000 claims 2
- 230000008878 coupling Effects 0.000 claims 1
- 238000010168 coupling process Methods 0.000 claims 1
- 238000005859 coupling reaction Methods 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 11
- 230000007423 decrease Effects 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 2
- 230000000295 complement effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Landscapes
- Dc-Dc Converters (AREA)
Description
本發明係有關一種斜波產生器(ramp generator)，更明確地說，係有關一種穩定可調變增益之斜波產生器。The present invention relates to a ramp generator, and more particularly to a ramp generator that stabilizes a variable gain.
請參考第1圖。第1圖係為說明一先前技術之降壓式(buck)電源轉換器100之示意圖。降壓式電源轉換器100係用來將一輸入電壓源VIN 之電壓降低以產生一輸出電壓VOUT 。降壓式電源轉換器100包含一功率開關Q1 、一電感L、一二極體D1 、一電容COUT 、兩電阻R1 及R2 ，以及一工作週期調整器110。工作週期調整器包含一比較器CMP1 、一誤差放大器111，以及一斜波產生器112。於第1圖中，各元件之連接關係已明顯揭露，於此不再贅述。其中VSS 為一電壓源，如地端。在第1圖中，電阻R1 及R2 根據輸出電壓VOUT ，產生回授電壓VFB 並傳送至誤差放大器111之負輸入端。誤差放大器111再根據回授電壓VFB 及參考電壓VREF ，產生責任電壓VDUTY ，並傳送至比較器CMP1 之輸入端。比較器CMP1 比較一來自於斜波產生器112之斜波訊號(ramp signal)VRAMP 以及責任電壓VDUTY ，據以產生開關控制訊號SSW 。開關控制訊號SSW 為一脈寬調變訊號(Pulse Width Modulation，PWM)。當開關控制訊號SSW 為低電壓準位時，功率開關Q1 導通；當開關控制訊號SSW 為高電壓準位時，功率開關Q1 關閉。因此，工作週期調整器110便可根據回授電壓VFB ，開關控制訊號SSW ，以決定功率開關Q1 是否導通，而使輸出電壓VOUT 之電壓準位維持在一預設電壓準位。Please refer to Figure 1. 1 is a schematic diagram illustrating a prior art buck power converter 100. The buck power converter 100 is configured to reduce the voltage of an input voltage source V IN to generate an output voltage V OUT . The buck power converter 100 includes a power switch Q 1 , an inductor L, a diode D 1 , a capacitor C OUT , two resistors R 1 and R 2 , and a duty cycle adjuster 110 . The duty cycle adjuster includes a comparator CMP 1 , an error amplifier 111 , and a ramp generator 112 . In the first figure, the connection relationship of each component has been clearly disclosed, and details are not described herein again. Where V SS is a voltage source, such as the ground. In the first figure, the resistors R 1 and R 2 generate a feedback voltage V FB according to the output voltage V OUT and are transmitted to the negative input terminal of the error amplifier 111. The error amplifier 111 generates a duty voltage V DUTY according to the feedback voltage V FB and the reference voltage V REF , and transmits it to the input terminal of the comparator CMP 1 . The comparator CMP 1 compares a ramp signal V RAMP from the ramp generator 112 and a duty voltage V DUTY to generate a switch control signal S SW . The switch control signal S SW is a Pulse Width Modulation (PWM). When the switch control signal S SW is at a low voltage level, the power switch Q 1 is turned on; when the switch control signal S SW is at a high voltage level, the power switch Q 1 is turned off. Therefore, the duty cycle adjuster 110 can switch the control signal S SW according to the feedback voltage V FB to determine whether the power switch Q 1 is turned on, and maintain the voltage level of the output voltage V OUT at a predetermined voltage level.
請參考第2圖。第2圖係為說明在第1圖中之開關控制訊號SSW 與輸出電壓VOUT 關係之示意圖。其中開關控制訊號SSW 之工作週期D、輸出電壓VOUT 與輸入電壓VIN 之間的關係可由下列公式表示：Please refer to Figure 2. Fig. 2 is a view showing the relationship between the switch control signal S SW and the output voltage V OUT in Fig. 1. The relationship between the duty cycle D of the switch control signal S SW , the output voltage V OUT and the input voltage V IN can be expressed by the following formula:
D=TON /TS =VDUTY /VRAMP_PTP ...(1)；D=T ON /T S =V DUTY /V RAMP_PTP ...(1);
VOUT /VIN =D=VDUTY /VRAMP_PTP ...(2)；V OUT /V IN =D=V DUTY /V RAMP_PTP ...(2);
其中TON 表示功率開關Q1 導通的時間，TS 表示開關控制訊號SSW 一個週期的時間、D表示工作週期、VRAMP_PTP 表示斜波訊號VRAMP 的峰對峰電壓(peak-to-peak voltage)。又降壓式電源轉換器100之可調變增益(Modulator Gain)GModulator 與迴路增益(Loop Gain)GLoop 可由下列公式表示：Where T ON represents the time when the power switch Q 1 is turned on, T S represents the time of the switch control signal S SW for one cycle, D represents the duty cycle, and V RAMP_PTP represents the peak-to-peak voltage of the ramp signal V RAMP (peak-to-peak voltage) ). The Modulator Gain G Modulator and the Loop Gain G Loop of the buck power converter 100 can be expressed by the following formula:
GModulator =ΔVOUT /ΔVDUTY =Δ[VIN ×(VDUTY /VRAMP_PTP )]/ΔVDUTY =VIN /VRAMP_PTP ...(3)；G Modulator = ΔV OUT / ΔV DUTY = Δ [V IN × (V DUTY / V RAMP_PTP )] / ΔV DUTY = V IN / V RAMP_PTP (3);
GLoop =(VIN /VRAMP_PTP )×(VREF /VOUT )=GModulator ×(VREF /VOUT )...(4)；G Loop = (V IN /V RAMP_PTP ) × (V REF /V OUT )=G Modulator ×(V REF /V OUT )...(4);
如第2圖所示，當輸入電壓VIN 下降時，輸出電壓VOUT 會隨之下降，而使回授電壓VFB 下降，因此責任電壓VDUTY 上升。此時比較器CMP1 比較斜波訊號VRAMP 及上升的責任電壓VDUTY 之後，會產生一具有較長之責任週期D之開關控制訊號SSW (如第2圖中時段Tx 所示)，而使輸出電壓VOUT 回升至預設電壓準位，然而在輸入電壓VIN 不穩定時(無論突升或突降)，由公式(3)與(4)可知，其將影響降壓式電源轉換器100之可調變增益GModulator 和迴路增益GLoop ，而使輸出電壓不穩定。As shown in Fig. 2, when the input voltage V IN drops, the output voltage V OUT decreases, and the feedback voltage V FB decreases, so the duty voltage V DUTY rises. At this time, after comparing the ramp signal V RAMP and the rising duty voltage V DUTY , the comparator CMP 1 generates a switch control signal S SW having a longer duty cycle D (as indicated by the time period T x in FIG. 2). And the output voltage V OUT is raised back to the preset voltage level, but when the input voltage V IN is unstable (whether rising or falling), it is known from equations (3) and (4) that it will affect the buck power supply. The variable gain G Modulator and the loop gain G Loop of the converter 100 make the output voltage unstable.
因此，在先前技術之電源轉換器中，當輸入電壓不穩定時，會影響電源轉換器的可調變增益而使輸出電壓變得不穩定，造成使用者極大的不便。Therefore, in the power converter of the prior art, when the input voltage is unstable, the adjustable gain of the power converter is affected and the output voltage becomes unstable, causing great inconvenience to the user.
本發明之一實施例係提供一種斜波產生器，可依據輸入訊號之變動而產生並調整斜波訊號，藉以穩定可調變增益。該斜波產生器包含一斜波電容、一充電電流模組，以及一放電模組。該斜波電容用來輸出該斜波訊號。該充電電流模組用來根據一輸入電壓源之電壓與一輸入參考電壓，產生一對應大小之充電電流，以對該斜波產生電容進行充電。該放電模組用以比較該斜波訊號以及一臨界電壓，以使該斜波產生電容放電，其中該臨界電壓係依據該充電電流而變化。An embodiment of the present invention provides a ramp generator that generates and adjusts a ramp signal according to a change in an input signal, thereby stabilizing the variable gain. The ramp generator includes a ramp capacitor, a charging current module, and a discharge module. The ramp capacitor is used to output the ramp signal. The charging current module is configured to generate a corresponding magnitude of charging current according to a voltage of an input voltage source and an input reference voltage to charge the ramp generating capacitor. The discharge module is configured to compare the ramp signal and a threshold voltage to cause the ramp to generate a capacitor discharge, wherein the threshold voltage varies according to the charge current.
本發明之一實施例提供一種穩定一電源轉換系統之可調變增益之方法。該方法包含根據一輸入電壓源之電壓，調整一充電電流、以該充電電流對一斜波產生電容充電，產生一斜波訊號、根據該輸入電壓源之電壓，調整一臨界電壓，以及當該斜波訊號大約高於或等於該臨界電壓時，對該斜波產生電容進行放電，以使該可調變增益大約為一定值。One embodiment of the present invention provides a method of stabilizing a variable gain of a power conversion system. The method comprises: adjusting a charging current according to a voltage of an input voltage source, charging a ramp generating capacitor with the charging current, generating a ramp signal, adjusting a threshold voltage according to the voltage of the input voltage source, and when When the ramp signal is higher than or equal to the threshold voltage, the ramp generating capacitance is discharged, so that the adjustable gain is about a certain value.
請參考第3圖。第3圖係為本發明較佳實施例之斜波產生器300之方塊圖。如第3圖所示，斜波產生器300包含一斜波電容CRAMP 、一充電電流模組310以及一放電模組320。藉由偵測輸入電壓VIN 之變化，斜波產生器300可產生並調整斜波訊號VRAMP 之峰對峰值VRAMP_PTP ，因而使得可調變增益約略維持一定值。Please refer to Figure 3. Figure 3 is a block diagram of a ramp generator 300 in accordance with a preferred embodiment of the present invention. As shown in FIG. 3, the ramp generator 300 includes a ramp capacitor C RAMP , a charging current module 310 , and a discharge module 320 . By detecting a change in the input voltage V IN , the ramp generator 300 can generate and adjust the peak-to-peak value V RAMP_PTP of the ramp signal V RAMP , thereby causing the adjustable gain to be approximately maintained at a certain value.
當斜波訊號VRAMP 降低至低臨界電壓VL (定值)時，充電電流模組310便會開始對斜波電容CRAMP 充電，以提升斜波訊號VRAMP 的電壓；當斜波訊號VRAMP 上升至高臨界電壓VH 之電壓準位時(大約等於或高於)，放電模組320對斜波電容CRAMP 進行放電，以降低斜波訊號VRAMP 。因此，斜波訊號VRAMP 的高峰值便為高臨界電壓VH ；斜波訊號VRAMP 的低峰值便為低臨界電壓VL 。換句話說，斜波訊號VRAMP 的峰對峰值VRAMP_PTP 便為(VH -VL )。斜波產生器300遂藉由充電電流模組310與放電模組320的反覆充放電過程而形成週期性的斜波訊號VRAMP 。When the ramp signal V RAMP is lowered to a low threshold voltage V L (set value), the charging current module 310 starts charging the ramp capacitor C RAMP to increase the voltage of the ramp signal V RAMP ; when the ramp signal V When the RAMP rises to the voltage level of the high threshold voltage V H (approximately equal to or higher than), the discharge module 320 discharges the ramp capacitor C RAMP to reduce the ramp signal V RAMP . Therefore, the high peak value of the ramp signal V RAMP is the high threshold voltage V H ; the low peak value of the ramp signal V RAMP is the low threshold voltage V L . In other words, the peak-to-peak value V RAMP_PTP of the ramp signal V RAMP is (V H - V L ). The ramp generator 300 形成 forms a periodic ramp signal V RAMP by the charging and discharging process of the charging current module 310 and the discharging module 320.
充電電流模組310之一電路實施方式係如第4圖所示，充電電流模組310包含一定電流源511以及一補充電流源512。定電流源511用來產生輸入參考電流IREF 、補充電流源512用來產生補充電流ΔI，而輸入參考電流IREF 與補充電流ΔI的和即為充電電流IC 。One circuit embodiment of the charging current module 310 is as shown in FIG. 4, and the charging current module 310 includes a constant current source 511 and a supplementary current source 512. The constant current source 511 is used to generate the input reference current I REF , the supplemental current source 512 is used to generate the supplemental current ΔI , and the sum of the input reference current I REF and the supplemental current ΔI is the charging current I C .
定電流源511包含一電晶體Q4 、一運算放大器OP3 以及一輸入參考電阻RREF 。運算放大器OP3 之一輸入端接收輸入參考電壓VIN_REF ；藉由運算放大器OP3 控制電晶體Q4 ，得定電流源511便可產生大小為(VIN_REF /RREF )的電流，並將其設為輸入參考電流IIN_REF 。The constant current source 511 includes a transistor Q 4 , an operational amplifier OP 3 , and an input reference resistor R REF . The operational amplifier OP 3, one input terminal receives the input reference voltage V IN_REF; 3 controlled by the operational amplifier OP transistor Q 4, to obtain the constant current source 511 can produce a size of (V IN_REF / R REF) current, and Set to input reference current I IN_REF .
補充電流源512包含兩電晶體Q2 及Q3 、兩運算放大器OP1 及OP2 以及一調整電阻RX1 。運算放大器OP1 之一輸入端接收輸入參考電壓VIN_REF 、運算放大器OP2 之一輸入端接收輸入電壓VIN ；藉由運算放大器OP1 與OP2 分別控制電晶體Q2 與Q3 ，補充電流源512便可產生大小為[(VIN -VIN_REF )/RX1 ]的電流，並將其設為補充電流ΔI。The supplemental current source 512 includes two transistors Q 2 and Q 3 , two operational amplifiers OP 1 and OP 2 , and an adjustment resistor R X1 . One of the operational amplifier OP 1 input terminal receives the input reference voltage V IN_REF, one of the operational amplifier OP input terminal receiving an input voltage V IN; by the operational amplifier OP 1 and OP 2 are the control transistor Q 2 and Q 3, complementary current Source 512 can generate a current of size [(V IN - V IN_REF ) / R X1 ] and set it as a supplemental current ΔI.
充電電流IC 可對斜波電容CRAMP 充電，其可以下式表示：The charging current I C charges the ramp capacitor C RAMP , which can be expressed as:
IC =IREF +ΔI=IREF +ΔVIN /RX =VIN_REF /RREF +(VIN -VIN_REF )/RX ...(5)；I C =I REF +ΔI=I REF +ΔV IN /R X =V IN_REF /R REF +(V IN -V IN_REF )/R X (5);
因此由上式可看出充電電流IC 會隨著輸入電壓VIN 改變而改變。Therefore, it can be seen from the above equation that the charging current I C changes as the input voltage V IN changes.
第5圖為本發明較佳實施例之斜波產生器之充電電流模組310之另一電路實施方式示意圖。如第5圖所示，充電電流模組310包含一定電流源611以及一補充電流源612。定電流源611運作原理與之前所述之定電流源511相同，於此不再贅述。FIG. 5 is a schematic diagram of another circuit embodiment of a charging current module 310 of a ramp generator according to a preferred embodiment of the present invention. As shown in FIG. 5, the charging current module 310 includes a constant current source 611 and a supplemental current source 612. The operation principle of the constant current source 611 is the same as that of the constant current source 511 described above, and will not be described herein.
補充電流源612包含一次補充電流源6121以及一乘法器6122。次補充電流源6121運作原理與第4圖中之補充電流源512相同，因此，電阻RX2 上會橫跨電壓差(VIN -VIN_REF )使得電晶體Q6 汲取的電流大小為[(VIN -VIN_REF )/RX2 ]，並將其設定為差異電流IM 。 乘法器6122包含一比較器CMP2 、一低通濾波器LPF、一開關SW1 以及一電阻RM 。乘法器6122係用來將次補充電流源6121所產生的差異電流IM ，乘以IIN_REF 倍，以產生補充電流ΔI。換句話說， 第5圖中之調整電阻RX2 的阻值應為第4圖中之調整電阻RX1 的阻值的IIN_REF 倍，如此補充電流源612與512所產生的補充電流ΔI大小便為相同。Supplemental current source 612 includes a primary supplemental current source 6121 and a multiplier 6122. The secondary supplemental current source 6121 operates in the same manner as the supplemental current source 512 in FIG. 4, and therefore, the voltage across the voltage difference (V IN -V IN — REF ) across the resistor R X2 causes the current drawn by the transistor Q 6 to be [(V). IN -V IN_REF ) / R X2 ] and set it to the difference current I M . The multiplier 6122 includes a comparator CMP 2 , a low pass filter LPF, a switch SW 1 , and a resistor R M . The multiplier 6122 is used to multiply the difference current I M generated by the secondary supplemental current source 6121 by I IN_REF times to generate the supplemental current ΔI. In other words , the resistance of the adjustment resistor R X2 in FIG. 5 should be I IN_REF times the resistance of the adjustment resistor R X1 in FIG. 4, thus supplementing the supplementary current ΔI generated by the current sources 612 and 512. For the same.
於乘法器6122中，比較器CMP2 接收一外部斜波訊號VRAMP_EXT 以及輸入參考電壓VIN_REF ；比較器CMP2 比較外部斜波訊號VRAMP_EXT 與輸入參考電壓VIN_REF ，以產生一開關控制訊號SM ， 來控制開關SW1 開啟或關閉。當開關SW1 開啟(其控制端1耦接至控制端2)時，差異電流IM 會直接流通到電壓源VCC 而不會流進低通濾波器LPF；反之，當開關SW1 關閉(其控制端1耦接至控制端C)時，差異電流IM 會直接流進低通濾波器LPF。而低通濾波器LPF係將流進低通濾波器LPF的差異電流IM 平均，如此以完成乘上IIN_REF 倍的效果。In the multiplier 6122, the comparator CMP 2 receives an external ramp signal V RAMP_EXT and an input reference voltage V IN — REF ; the comparator CMP 2 compares the external ramp signal V RAMP — EXT with the input reference voltage V IN — REF to generate a switch control signal S M, to control out switch SW 1 is turned on or off. When the switch SW 1 is turned on (the control terminal 1 is coupled to the control terminal 2), the differential current I M flows directly to the voltage source V CC without flowing into the low pass filter LPF; conversely, when the switch SW 1 is turned off ( When the control terminal 1 is coupled to the control terminal C), the difference current I M flows directly into the low pass filter LPF. The low pass filter LPF averages the difference current I M flowing into the low pass filter LPF, thus achieving the effect of multiplying the I IN_REF times.
此外，放電模組320之一電路實施方式係如第6圖所示，放電模組320包含一比較器CMP3 、一開關SW2 、一臨界電壓電路321以及一放電電源322。臨界電壓電路321根據來自充電電流模組310之充電電流IC ，以產生高臨界電壓VH ，並輸入至比較器CMP1 之負輸入端。於第6圖中，臨界電壓電路321可以一臨界電阻RH 來實現。比較器CMP3 用來接收斜波訊號VRAMP 與高臨界電壓VH ，並比較斜波訊號VRAMP 與高臨界電壓VH 以產生放電觸發訊號Sc 。當斜波訊號VRAMP 上升至高臨界電壓VH 之電壓準位時(大約等於或高於)，比較器CMP3 輸出代表「導通」的放電觸發訊號Sc 至開關SW2 之控制端C，以使開關SW2 之控制端1耦接開關SW2 之控制端2。因此，放電電源322透過開關SW2 耦接至斜波電容CRAMP ，而從斜波電容CRAMP 汲取放電電流ID ，以對斜波電容CRAMP 進行放電，來降低斜波訊號VRAMP 。此外，放電電源322可以一電壓源VD 來實現。In addition, one circuit embodiment of the discharge module 320 is as shown in FIG. 6. The discharge module 320 includes a comparator CMP 3 , a switch SW 2 , a threshold voltage circuit 321 , and a discharge power source 322 . The threshold voltage circuit 321 generates a high threshold voltage V H based on the charging current I C from the charging current module 310 and inputs it to the negative input terminal of the comparator CMP 1 . In FIG. 6, the threshold voltage circuit 321 can be implemented with a threshold resistance R H . The comparator CMP 3 is configured to receive the ramp signal V RAMP and the high threshold voltage V H and compare the ramp signal V RAMP with the high threshold voltage V H to generate the discharge trigger signal S c . When the ramp signal V RAMP rises to a voltage level of the high threshold voltage V H (approximately equal to or higher than), the comparator CMP 3 outputs a discharge trigger signal S c representing "on" to the control terminal C of the switch SW 2 to the control terminal of switch SW 2 of the control switch SW 1 is coupled to terminal 2 of 2. Thus, discharge power supply 322 through the switch SW 2 is coupled to the ramp capacitor C RAMP, and the discharge current I D drawn from the ramp capacitor C RAMP, on the ramp to discharge the capacitor C RAMP, to reduce the ramp signal V RAMP. Additionally, the discharge source 322 can be implemented as a voltage source V D .
本實施例中放電模組320的高臨界電壓VH 會動態地改變。更明確地說，放電模組320係根據充電電流Ic 的大小，決定高臨界電壓VH 的大小。高臨界電壓VH 可以下式表示：In this embodiment, the high threshold voltage V H of the discharge module 320 is dynamically changed. More specifically, the discharge module 320 determines the magnitude of the high threshold voltage V H based on the magnitude of the charging current I c . The high threshold voltage V H can be expressed by the following formula:
VH =VH_REF +ΔVH =VH_REF +ΔI×RH ...(6)；V H =V H_REF +ΔV H =V H_REF +ΔI×R H (6);
其中VH_REF 表示高臨界參考電壓(定值)、ΔVH 表示補充臨界電壓、RH 表示臨界電阻；ΔVH 等於ΔI×RH (隨輸入電壓VIN 改變而改變)，因此由上式可看出高臨界電壓VH 會隨著充電電流IC 改變而改變。而由於斜波訊號VRAMP 的峰對峰值VRAMP_PTP 為(VH -VL )，且低臨界電壓VL 為定值，因此斜波訊號VRAMP 的峰對峰值VRAMP_PP 便會隨著高臨界電壓VH 而改變。更進一步地說，由於輸入電壓VIN 會影響充電電流IC 的大小，且充電電流IC 亦會影響高臨界電壓VH 的大小，因此可推知斜波訊號VRAMP 的峰對峰值VRAMP_PTP 會隨著輸入電壓VIN 的大小而改變。也就是說，當輸入電壓VIN 改變時，斜波訊號VRAMP 的峰對峰值VRAMP_PTP 會隨之改變，因而能夠使得可調變增益約略穩定於一定值。Where V H_REF denotes a high critical reference voltage (fixed value), ΔV H denotes a supplementary threshold voltage, R H denotes a critical resistance; ΔV H is equal to ΔI×R H (changes with an input voltage V IN ), so it can be seen from the above formula The high threshold voltage V H changes as the charging current I C changes. Since the peak-to-peak V RAMP_PTP of the ramp signal V RAMP is (V H -V L ) and the low threshold voltage V L is constant, the peak-to-peak V RAMP_PP of the ramp signal V RAMP will follow the high threshold. The voltage V H changes. More particularly, since the input voltage V IN will affect the magnitude of the charging current I C, and the charging current I C will also affect the magnitude of the high threshold voltage V H, and therefore can be extrapolated peak of ramp signal V RAMP will peak V RAMP_PTP It changes with the magnitude of the input voltage V IN . That is to say, when the input voltage V IN is changed, the peak-to-peak value V RAMP_PTP of the ramp signal V RAMP changes accordingly, so that the adjustable variable gain can be stabilized to a certain value.
第7圖係本發明較佳實施例之斜波產生器中相關訊號之示意圖。從第7圖可看出，本發明之精神係在於當輸入電壓VIN 改變時，充電電流IC 的大小與高臨界電壓VH 的大小隨之改變，而使斜波訊號VRAMP 之峰對峰值VRAMP_PTP 也跟著改變，如此一來可調變增益將約略穩定於一定值。如第7圖所示，當輸入電壓VIN 上升(增加ΔVIN )時，充電電流IC 上升(增加ΔI)、高臨界電壓VH 亦上升(增加ΔVH )，而斜波訊號VRAMP 的峰對峰值VRAM P_PTP 亦隨之改變，如此以讓可調變增益維持為定值。Figure 7 is a schematic diagram of related signals in a ramp generator of a preferred embodiment of the present invention. As can be seen from Fig. 7, the spirit of the present invention is that when the input voltage V IN is changed, the magnitude of the charging current I C and the magnitude of the high threshold voltage V H are changed, and the peak of the ramp signal V RAMP is made. The peak V RAMP_PTP is also changed, so that the adjustable gain will be approximately stable to a certain value. As shown in Fig. 7, when the input voltage V IN rises (increases ΔV IN ), the charging current I C rises (increases ΔI), the high threshold voltage V H also rises (increases ΔV H ), and the ramp signal V RAMP The peak-to-peak V RAM P _PTP also changes, so that the adjustable gain is maintained at a constant value.
第8圖係本發明較佳實施例之斜波產生器300之電路示意圖。於第8圖中，充電電流模組310係以第5圖之電路實施方式為例以使讀者充分了解；然亦可以第4圖之實施方式或其他方式來實現。於第8圖中，額外增加了電晶體Q7 、Q8 與Q9 。電晶體Q7 與Q8 形成一電流鏡以複製充電電流IC ，來對斜波電容CRAMP 充電。電晶體Q7 與Q9 形成另一電流鏡，以複製充電電流IC ，以使臨界電阻RH 上產生臨界電壓VH 。充電電流模組310之工作原理與與結構如同第5圖所示。充電電流模組310根據輸入參考電壓VIN_REF 以及輸入電壓源VIN 之電壓(設為輸入電壓VIN )，產生一充電電流IC 。第8圖之電路運作原理與前述相同，於此不再贅述。Figure 8 is a circuit diagram of a ramp generator 300 in accordance with a preferred embodiment of the present invention. In Fig. 8, the charging current module 310 is exemplified by the circuit embodiment of Fig. 5 for the reader to fully understand; however, it can also be implemented by the embodiment of Fig. 4 or other means. In Fig. 8, transistors Q 7 , Q 8 and Q 9 are additionally added. The transistors Q 7 and Q 8 form a current mirror to replicate the charging current I C to charge the ramp capacitor C RAMP . Transistor Q 7 form another current mirror and Q 9, in order to copy the charging current I C, so that the threshold resistance R H is generated on the threshold voltage V H. The working principle and structure of the charging current module 310 are as shown in FIG. The charging current module 310 generates a charging current I C according to the input reference voltage V IN — REF and the voltage of the input voltage source V IN (set to the input voltage V IN ). The circuit operation principle of FIG. 8 is the same as the foregoing, and will not be described herein.
此外，雖然於本發明之實施例中，僅舉輸入電壓VIN 升高為例，然而輸入電壓VIN 下降的情況，亦包含於本發明中。更明確地說，當輸入電壓VIN 下降時，充電電流IC 與高臨界電壓VH 亦會隨之下降，以調降斜波訊號VRAMP 的峰對峰值VRAMP_PTP ，來使得可調變增益仍能約略穩定於一定值。Further, although in the embodiment of the present invention, only the input voltage V IN is raised as an example, the case where the input voltage V IN is lowered is also included in the present invention. More specifically, when the input voltage V IN drops, the charging current I C and the high threshold voltage V H also decrease to lower the peak-to-peak value V RAMP_PTP of the ramp signal V RAMP to make the variable gain Still can be stable to a certain value.
請參考第9圖。第9圖係為應用本發明之斜波產生器之降壓式電源轉換器900之示意圖。除了斜波產生器300之外，降壓式電源轉換器900之結構及工作原理與第1圖中降壓式電源轉換器100類似，故不再贅述。由於降壓式電源轉換器900使用了本發明之斜波產生器300，因此其可調變增益不會隨著輸入電壓VIN 改變而改變，而是維持在一定值。如此降壓式電源轉換器900便可提供穩定的輸出電壓VOUT 。Please refer to Figure 9. Figure 9 is a schematic diagram of a buck power converter 900 to which the ramp generator of the present invention is applied. The structure and operation principle of the buck power converter 900 are similar to those of the buck power converter 100 of FIG. 1 except for the ramp generator 300, and therefore will not be described again. Since the buck power converter 900 uses the ramp generator 300 of the present invention, its adjustable gain does not change as the input voltage V IN changes, but is maintained at a constant value. Such a buck power converter 900 can provide a stable output voltage V OUT .
此外，雖然於本發明中僅舉應用本發明之斜波產生器之降壓式電源轉換器為例，然其他類型之電源轉換器，如升壓式電源轉換器、升/降壓式電源轉換器，皆可利用本發明之斜波產生器，以得到不隨輸入電壓改變的可調變增益。其他類型之電源轉換器為業界所習知，故不在本文中贅述。In addition, although the buck power converter to which the ramp generator of the present invention is applied is exemplified in the present invention, other types of power converters such as a boost power converter and a step-up/step power converter are used. The ramp generator of the present invention can be utilized to obtain a variable gain that does not vary with the input voltage. Other types of power converters are well known in the industry and are not described here.
綜上所述，本發明之斜波產生器可根據輸入電壓以調整斜波訊號。因此，利用本發明之斜波產生器，當電源轉換器之輸入電壓不穩定時，電源轉換器之可調變增益仍可維持不變，進而產生更穩定的輸出電壓，提供給使用者更大的便利性。In summary, the ramp generator of the present invention can adjust the ramp signal according to the input voltage. Therefore, with the ramp generator of the present invention, when the input voltage of the power converter is unstable, the adjustable gain of the power converter can be maintained, thereby generating a more stable output voltage and providing the user with a larger output voltage. Convenience.
以上所述僅為本發明之較佳實施例，凡依本發明申請專利範圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.
100、900．．．降壓式電源轉換器100, 900. . . Buck power converter
110．．．工作週期調整器110. . . Work cycle adjuster
111．．．誤差放大器111. . . Error amplifier
112、300．．．斜波產生器112, 300. . . Ramp generator
310．．．充電電流模組310. . . Charging current module
320．．．放電模組320. . . Discharge module
321．．．臨界電壓電路321. . . Critical voltage circuit
322．．．放電電源322. . . Discharge power supply
511、611．．．定電流源511, 611. . . Constant current source
512、612．．．補充電流源512, 612. . . Supplementary current source
6121．．．次補充電流源6121. . . Secondary supplemental current source
6122．．．乘法器6122. . . Multiplier
CMP1 、CMP2 、CMP3 ．．．比較器CMP 1 , CMP 2 , CMP 3 . . . Comparators
D1 ．．．二極體D 1 . . . Dipole
IC ．．．充電電流I C . . . recharging current
ID ．．．放電電流I D . . . Discharge current
IM ．．．差異電流I M . . . Differential current
IREF ．．．輸入參考電流I REF . . . Input reference current
L．．．電感L. . . inductance
LPF．．．低通濾波器LPF. . . Low pass filter
OP1 、OP2 、OP3 、OP4 、OP5 ．．．運算放大器OP 1 , OP 2 , OP 3 , OP 4 , OP 5 . . . Operational Amplifier
Q1 ．．．功率開關Q 1 . . . Power switch
Q2 、Q3 、Q4 、Q5 、Q6 、Q7 、Q8 、Q9 ．．．電晶體Q 2 , Q 3 , Q 4 , Q 5 , Q 6 , Q 7 , Q 8 , Q 9 . . . Transistor
R1 、R2 、RM ．．．電阻R 1 , R 2 , R M . . . resistance
RH ．．．臨界電阻R H . . . Critical resistance
RX ．．．調整電阻R X . . . Adjustment resistance
SC ．．．放電觸發訊號S C . . . Discharge trigger signal
SSW 、SM ．．．開關控制訊號S SW , S M . . . Switch control signal
SW1 、SW2 ．．．開關SW 1 , SW 2 . . . switch
TON 、TX ．．．導通時間T ON , T X . . . On time
TS ．．．週期T S . . . cycle
VDUTY ．．．責任電壓V DUTY . . . Liability voltage
VFB ．．．回授電壓V FB . . . Feedback voltage
VH ．．．臨界電壓V H . . . Threshold voltage
VH_REF ．．．臨界參考電壓V H_REF . . . Critical reference voltage
VIN ．．．輸入電壓V IN . . . Input voltage
VIN_REF ．．．輸入參考電壓V IN_REF . . . Input reference voltage
VOUT ．．．輸出電壓V OUT . . . The output voltage
VRAMP ．．．斜波訊號V RAMP . . . Oblique wave signal
VRAMP_EXT ．．．外部斜波訊號V RAMP_EXT . . . External ramp signal
VREF ．．．參考電壓V REF . . . Reference voltage
VCC 、VSS 、VD ．．．電壓源V CC , V SS , V D . . . power source
ΔI．．．補充電流ΔI. . . Supplementary current
ΔVH ．．．臨界電壓差ΔV H . . . Critical voltage difference
ΔVIN ．．．輸入電壓差ΔV IN . . . Input voltage difference
第1圖係為說明一先前技術之降壓式電源轉換器之示意圖。Figure 1 is a schematic diagram illustrating a prior art buck power converter.
第2圖係為說明在第1圖中之開關控制訊號與輸出電壓關係之示意圖。Figure 2 is a schematic diagram showing the relationship between the switching control signal and the output voltage in Figure 1.
第3圖係為本發明之可維持可調變增益不變之斜波產生器之方塊圖。Figure 3 is a block diagram of the ramp generator of the present invention which maintains the variable gain constant.
第4圖係為本發明之斜波產生器之充電電流模組之第一實施例之示意圖。Figure 4 is a schematic view showing a first embodiment of a charging current module of the ramp generator of the present invention.
第5圖係為本發明之斜波產生器之充電電流模組之第二實施例之示意圖。Figure 5 is a schematic view showing a second embodiment of the charging current module of the ramp generator of the present invention.
第6圖係為本發明之放電模組之實施例之示意圖。Figure 6 is a schematic view of an embodiment of a discharge module of the present invention.
第7圖係為說明本發明之斜波產生器所產生之斜波訊號根據輸入電壓改變而維持可調變增益不變之示意圖。Fig. 7 is a view for explaining that the ramp signal generated by the ramp generator of the present invention maintains the variable gain constant according to the input voltage change.
第8圖係為本發明之斜波產生器之電路示意圖。Figure 8 is a circuit diagram of the ramp generator of the present invention.
第9圖係為應用本發明之斜波產生器之降壓式電源轉換器之示意圖。Figure 9 is a schematic diagram of a buck power converter to which the ramp generator of the present invention is applied.
300．．．斜波產生器300. . . Ramp generator
310．．．充電電流模組310. . . Charging current module
320．．．放電模組320. . . Discharge module
IC ．．．充電電流I C . . . recharging current
ID ．．．放電電流I D . . . Discharge current
CRAMP ．．．斜波電容C RAMP . . . Ripple capacitor
VRAMP ．．．斜波訊號V RAMP . . . Oblique wave signal
VSS ．．．電壓源V SS . . . power source
VIN ．．．輸入電壓V IN . . . Input voltage
VIN_REF ．．．輸入參考電壓V IN_REF . . . Input reference voltage
Claims (8)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW98120843A TWI399037B (en) | 2009-06-22 | 2009-06-22 | Ramp generator capable of stabilizing modulator gain, power converting system, and method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW98120843A TWI399037B (en) | 2009-06-22 | 2009-06-22 | Ramp generator capable of stabilizing modulator gain, power converting system, and method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| TW201101690A TW201101690A (en) | 2011-01-01 |
| TWI399037B true TWI399037B (en) | 2013-06-11 |
Family
ID=44837093
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| TW98120843A TWI399037B (en) | 2009-06-22 | 2009-06-22 | Ramp generator capable of stabilizing modulator gain, power converting system, and method thereof |
Country Status (1)
| Country | Link |
|---|---|
| TW (1) | TWI399037B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI470908B (en) * | 2012-08-21 | 2015-01-21 | Upi Semiconductor Corp | Control circuit, time calculating unit, and operating method for control circuit |
| CN104377959B (en) * | 2013-08-16 | 2017-04-26 | 台达电子企业管理（上海）有限公司 | Power converter and method for stabilizing voltage gain |
| TWI655819B (en) * | 2017-11-24 | 2019-04-01 | 致茂電子股份有限公司 | Control method for a switching power supply apparatus |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6449175B1 (en) * | 2000-08-11 | 2002-09-10 | Astec International Limited | Switched magamp post regulator |
| US6452425B1 (en) * | 2001-02-13 | 2002-09-17 | Exar Corporation | Automatic frequency rate switch |
| TW200516830A (en) * | 2003-11-14 | 2005-05-16 | Beyond Innovation Tech Co Ltd | A pulse width modulation control circuit and the loading system of its application |
| TW200841568A (en) * | 2007-03-09 | 2008-10-16 | O2Micro Inc | Current-mode DC-to-DC converter, method for converting and electronic system thereof |
-
2009
- 2009-06-22 TW TW98120843A patent/TWI399037B/en not_active IP Right Cessation
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6449175B1 (en) * | 2000-08-11 | 2002-09-10 | Astec International Limited | Switched magamp post regulator |
| US6452425B1 (en) * | 2001-02-13 | 2002-09-17 | Exar Corporation | Automatic frequency rate switch |
| TW200516830A (en) * | 2003-11-14 | 2005-05-16 | Beyond Innovation Tech Co Ltd | A pulse width modulation control circuit and the loading system of its application |
| TW200841568A (en) * | 2007-03-09 | 2008-10-16 | O2Micro Inc | Current-mode DC-to-DC converter, method for converting and electronic system thereof |
Non-Patent Citations (1)
| Title |
|---|
| Jia, J.B.; Leung, K.N.; , "Integrated ramp generator with auto-set hysteretic comparator for PWM voltage regulators," Electronics Letters , vol.43, no.24, pp.1384-1385, Nov. 22 2007。 * |
Also Published As
| Publication number | Publication date |
|---|---|
| TW201101690A (en) | 2011-01-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7199563B2 (en) | DC-DC converter | |
| US7489121B2 (en) | Compensation offset adjustment scheme for fast reference voltage transitioning | |
| US11381167B2 (en) | Power converter with slope compensation | |
| TWI479790B (en) | Switching-mode power supply with ripple mode control and associated methods | |
| JP4725641B2 (en) | Buck-boost switching regulator | |
| JP5464695B2 (en) | DC-DC converter, DC voltage conversion method | |
| TWI385907B (en) | Dc-dc converter | |
| US7446520B2 (en) | PWM controller for a voltage regulator | |
| US8253507B2 (en) | Fixed-frequency control circuit and method for pulse width modulation | |
| US8698476B2 (en) | Control circuit and method for a current mode controlled power converter | |
| US8760137B2 (en) | DC-DC converter control circuit and DC-DC converter including same | |
| TWI434499B (en) | Frequency jitter controller and frequency jitter control method for power converter | |
| US8760138B2 (en) | DC-DC converter control circuit and DC-DC converter including same | |
| US8760139B2 (en) | DC-DC converter control circuit and DC-DC converter including same | |
| JP2012510247A (en) | Switch mode voltage regulator | |
| EP2973972A1 (en) | Duty-cycle dependent slope compensation for a current mode switching regulator | |
| JP2009153289A (en) | Dc-dc converter | |
| US9024610B2 (en) | System and method of balanced slope compensation for switch mode regulators | |
| US9467044B2 (en) | Timing generator and timing signal generation method for power converter | |
| US11018581B2 (en) | Methods and devices for operating converters | |
| CN113726159B (en) | Buck converter and electronic device | |
| TWI399037B (en) | Ramp generator capable of stabilizing modulator gain, power converting system, and method thereof | |
| US7990116B2 (en) | Modulator with linear period stretching capability | |
| TWM454670U (en) | DC-DC converter | |
| US8018207B2 (en) | Switching regulator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MM4A | Annulment or lapse of patent due to non-payment of fees |