CN101106361A - Mutually supplementary gain control circuit - Google Patents
Mutually supplementary gain control circuit Download PDFInfo
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- CN101106361A CN101106361A CNA2006100987606A CN200610098760A CN101106361A CN 101106361 A CN101106361 A CN 101106361A CN A2006100987606 A CNA2006100987606 A CN A2006100987606A CN 200610098760 A CN200610098760 A CN 200610098760A CN 101106361 A CN101106361 A CN 101106361A
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- voltage
- control circuit
- gain control
- oblique wave
- comparing unit
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Abstract
The invention discloses a complementary gain control circuit applied to a class D audio power amplifier, comprising a voltage dividing unit, a first comparing unit, a ramp wave generating unit, and a second comparing unit through all of which the duty ratio can be adjusted according to the differential voltage of high voltage and low voltage so that the power gain loss can be made up and class D audio power amplifier in different voltage still can keep fixed output power or power gain.
Description
Technical field
What the present invention relates to is a kind of mutually supplementary gain control circuit, particularly be a kind of D of making genus audio power amplifier when different supply voltages, still can keep a fixing power output or the circuit of power gain.
Background technology
The operation principle of D genus audio power amplifier, it is to use audio signal to come the modulation carrier wave, and make its output signal is the switch signal of PWM (PulseWidthModulation), therefore when input voltage is no-voltage, the duty ratio of this PWM (dutycycle) then is 50%, and when input voltage is positive voltage, duty ratio is then greater than 50%, and if when input voltage is negative voltage, this duty ratio is then little of 50%, is supply voltage by the high voltage at this switch signal, and its low-voltage is a no-voltage, so when the PWM signal had one fixedly modulation is than (that is having a fixed duty cycle), this power output promptly descended with the decline of supply voltage;
At present habitual loop (open-loop) the D genus audio power amplifier of opening, as previously mentioned one fixedly during input signal (that is a fixed duty cycle is arranged), its power output is that the decline with supply voltage descends, this moment, the overall power gain of power amplifier also descended along with the decline of supply voltage, therefore when the D class A amplifier A uses battery supply, then the power gain of amplifier can descend along with the decline of cell voltage, and when power output drops to a certain degree, then often takeed for the battery electric power deficiency and changed battery, at this moment, as the still surplus waste that has electric power then will cause battery of battery, and export in order to be apt to battery electric power or to keep stable volume, the D class audio amplifier needs stable power gain;
General A category-B audio-frequency power amplifier is a mode of using negative feedback (negative-feedback), that is loop circuit (close-loop) mode, voltage gain is not changed with supply voltage, to reach the purpose of stablizing power output, and with the D power-like amplifier, use the loop circuit mode then its degenerative circuit with relative complex, this is because the output signal of D class A amplifier A is the switch signal of PWM, its contained harmonic wave is high, and, in order essence to get audio signal to do the usefulness of feedback, its unnecessary high-frequency harmonic is essential to be filtered through low pass filter earlier, thereby causes cost to increase, high-frequency harmonic disturbs and increases the problems such as degree of difficulty of circuit layout (layout);
Therefore, this case inventor a kind ofly uses complementary (compensated) control mode opening under the mode in loop and research and develop, in view of the above-mentioned problems to remove the mutually supplementary gain control circuit of supply voltage to the power output influence.
Summary of the invention
Main purpose of the present invention provides a kind of mutually supplementary gain control circuit, by adjusting the loss that duty recently remedies power gain to utilize, and then reach and make its D genus audio power amplifier when different supply voltages, still can keep a fixing power output or the effect of power gain.
For achieving the above object, the technical solution used in the present invention is, a kind of mutually supplementary gain control circuit is provided, be applied in the D genus audio power amplifier, it comprises a partial pressure unit, one first comparing unit, an oblique wave generation unit and one second comparing unit, see through this partial pressure unit, first comparing unit, oblique wave generation unit and second comparing unit, and according to the magnitude of pressure differential of the high levle voltage and the low level voltage of its input of supply voltage, adjusted duty ratio, by adjusting the loss that duty recently remedies power gain to utilize;
The complementary gain control mode of the adjustment duty ratio by this partial pressure unit, first comparing unit, oblique wave generation unit and second comparing unit can further be apt to the electric power resource that is stored in inside battery.
Advantage of the present invention:
1. when different supply voltages, still power output or power gain can be kept in the fixed range;
2. the battery replacement of avoiding remaining power supply abandons, and causes the power resource waste.
Below in conjunction with accompanying drawing, be described in more detail with other technical characterictic and advantage the present invention is above-mentioned.
Description of drawings
Circuit diagram when Fig. 1 rises for its ramp voltage of the present invention;
The pulse wave schematic diagram that Fig. 2 is produced when rising and descending for its ramp voltage of the present invention;
Circuit diagram when Fig. 3 descends for its ramp voltage of the present invention;
The schematic diagram of output pulse wave when Fig. 4 is its mains voltage variations of the present invention.
Description of reference numerals: 21-partial pressure unit; 211-high levle voltage; 212-low level voltage; The 213-earth potential; 22-first comparing unit; 221-high levle voltage input end; 222-low level voltage input end; 223-ramp signal input; 224-controlling signal output; 23-oblique wave generation unit; The 231-current source; The 232-source of charging; The 233-discharge source; The 234-capacitor; The 235-ramp voltage; The 236-ramp voltage; 24-second comparing unit; The 241-negative input end; The 242-positive input terminal; The 243-signal output end; 244A-pulse wave signal; 244B-pulse wave signal; The 245-input signal.
Embodiment
The present invention provides a kind of mutually supplementary gain control circuit, it is to use the D genus audio power amplifier: power output=(supply voltage VCC * supply voltage VCC/ output loading R) * duty ratio, wherein, duty ratio (dutycycle)=pulse bandwidth (pulsewidth)/pulse wave cycle (pulseperiod) as shown from the above formula power output descend along with the decline of supply voltage, but rise along with the rising of duty ratio; Therefore the present invention promptly utilizes the adjustment of duty ratio in the above-mentioned formula (dutycycle), reach and make its D genus audio power amplifier when different supply voltages (VCC), still can keep a fixing power output or a power gain, see also shown in Figure 1ly, this circuit is to comprise:
One partial pressure unit 21, it is that these partial pressure unit 21 1 ends are connected to supply voltage (VCC), the other end then is connected to earth potential 213, this partial pressure unit 21 is provided with high levle voltage 211 and a low level voltage 212, this high levle voltage 211 is connected to the high levle voltage input end 221 (HIIN) of one first comparing unit 22, this low level voltage 212 is connected to the low level voltage input end 222 (LOWIN) of first comparing unit 22, wherein, the supply voltage (VCC) that is connected when this partial pressure unit 21 is when beginning to descend, high levle voltage 211 that this partial pressure unit 21 is set and low level voltage 212 also with decline, therefore when this high levle voltage 211 and low level voltage 212 descend because of the decline with supply voltage (VCC), please cooperate and consult Fig. 4, the pressure reduction that its high levle voltage 211 and low level voltage are 212 with dwindle, and when the pressure reduction of 212 of this high levle voltage 211 and low level voltages dwindles, it is inputed to the ramp voltage 235 of first comparing unit 22 by an oblique wave generation unit 23,236 amplitude also can with dwindle, see through the high levle voltage 211 of this partial pressure unit 21, and low level voltage 212 changes, can produce high levle voltage 211 for its first comparing unit 22 along with supply voltage, and the ramp voltage 235 of low level voltage 212 variations, 236, and one second comparing unit 24 that passes through to be arranged in pairs or groups adjusts the duty ratio of its output pulse wave, and then utilize to adjust the loss that duty recently remedies power gain.As shown in Figure 4, high levle voltage 211 diminishes with the pressure reduction of low level voltage 212 when supply voltage descends, and the output duty cycle of second comparing unit 24 promptly becomes the bigger pulse wave signal 244B of duty ratio by the pulse wave of original pulse wave signal 244A;
One first comparing unit 22, it is to be provided with a high levle voltage input end 221 (HIIN), a low level voltage input end 222 (LOWIN), a ramp signal input 223 (RAMPIN), an and controlling signal output 224 (OUT), wherein, this controlling signal output 224 (OUT) is to be connected with the current source 231 of an oblique wave generation unit 23, and this ramp signal input 223 (RAMPIN) is to be connected with the capacitor 234 of oblique wave generation unit 23 again;
One oblique wave generation unit 23, it is to produce a ramp voltage (being ramp signal) 235,236, this oblique wave generation unit 23 is made of a current source 231 and a capacitor 234, this current source 231 is respectively equipped with a charging source 232 and a discharge source 233, wherein, when the current source 231 of oblique wave generation unit 23 is charging source 232, promptly charge to capacitor 234 in this charging source 232, make it be linear rising via the ramp voltage 235 that capacitor 234 inputs to ramp signal input 223 (RAMPIN), until the high levle voltage 211 that reaches first comparing unit, 22 its high levle voltage input ends 221 (HIIN), promptly pass through the controlling signal output 224 (OUT) of this first comparing unit 22, export the current source 231 that a controlling signal gives oblique wave generation unit 23, please consult shown in Figure 3 again, and make current source 231 switch to discharge source 233 by charging source 232, please cooperate again and consult Fig. 2, make the ramp voltage 236 in its first comparing unit 22 be linear decline immediately, when ramp voltage 236 drops to the low level voltage 212 of first comparing unit, 22 its low level voltage input ends 222 (LOWIN), the controlling signal output 224 (OUT) of this first comparing unit 22, promptly export the current source 231 that a controlling signal gives oblique wave generation unit 23, please consult Fig. 1 again, make current source 231 switch to charging source 232 by discharge source 233, and begin its capacitor 234 is charged, and being with linearity again, its ramp voltage 235 rises, high levle voltage 211 by high levle voltage input end 221 (HIIN), and the low level voltage 212 of low level voltage input end 222 (LOWIN), make the discharge source 233 of current source 231 constantly repeat to switch, and then produce the required ramp voltage 235 of one second comparing unit 24 with charging source 232,236;
One second comparing unit 24, it is to be provided with a negative input end 241, one positive input terminal 242 and a signal output end 243, this negative input end 241 is to be connected with oblique wave generation unit 23, see also Fig. 1, cooperate Fig. 4, this positive input terminal 242 is to be connected with an input signal 245 (IN), see through this second comparing unit 24, please consult Fig. 1 again, cooperate 2, Fig. 4, ramp voltage 235 with 23 outputs of oblique wave generation unit, 236 are switched generation one pulse wave signal 244A with the input signal 245 (IN) of positive input terminal 242, and with this pulse wave signal 244A via signal output end 243 output, when supply voltage (VCC) descends by reducing at the high levle voltage 211 of partial pressure unit 21 and the pressure reduction of low level voltage 212, second comparing unit 24 is promptly exported pulse wave signal such as the 244B than big space rate, so utilizes the purpose of transferring duty recently to remedy the loss of power gain;
By the above as can be known power output be that decline along with its supply voltage (VCC) descends, but rise along with the rising of duty ratio, therefore, when supply voltage (VCC) descends, can change according to the high levle voltage 211 of supply voltage (VCC) input and the pressure reduction of low level voltage 212, adjusted the output oblique wave of oblique wave generation unit 23, thereby control second comparing unit, 24 its output duty cycles such as 244B to remedy the loss of power gain, and make its D genus audio power amplifier when different supply voltages (VCC), still can keep a power output of fixing or the effect of power gain.
In like manner power output rises along with the rising of supply voltage (VCC), but descend along with the decline of duty ratio, therefore, when supply voltage (VCC) rises, the high levle voltage 211 of supply voltage (VCC) input and the pressure reduction of low level voltage 212 become big, the output oblique wave amplitude of oblique wave generation unit 23 promptly rises, thereby the width that reduces by second comparing unit, 24 its output pulse waves is than the rising with oppressive power gain, and make its D genus audio power amplifier when different supply voltages (VCC), still can keep a power output of fixing or the effect of power gain;
On the other hand, the complementary gain control mode of the adjustment duty ratio by this partial pressure unit 21, comparing unit 22 and oblique wave generation unit 23, second comparing unit 24, can further be apt to the electric power resource that is stored in inside battery, and then avoid having the battery replacement of electric power to abandon balance, and cause the waste of available power resource.
In sum, the present invention is breaking through under the previous technical pattern, has reached the effect that institute's desire is promoted really, and also non-be familiar with this skill person institute easily think and, on the other hand, before the present patent application not openly, the progressive of its tool, practicality.
The above only is preferred embodiment of the present invention, only is illustrative for the purpose of the present invention, and nonrestrictive.Those skilled in the art is understood, and can carry out many changes to it in the spirit and scope that claim of the present invention limited, revise, even equivalence, but all will fall within the scope of protection of the present invention.
Claims (10)
1. a mutually supplementary gain control circuit is to be applied in the D genus audio power amplifier, it is characterized in that, comprises:
One partial pressure unit, it is to be provided with high levle voltage and a low level voltage, and this high levle voltage is connected to the high levle voltage input end of one first comparing unit, and this low level voltage is connected to the low level voltage input end of first comparing unit;
One oblique wave generation unit, it is made of a current source and a capacitor;
One first comparing unit, the controlling signal output of this first comparing unit is connected with the current source of oblique wave generation unit, and the ramp signal input is connected with the capacitor of oblique wave generation unit;
One second comparing unit, it is to be provided with a negative input end, a positive input terminal and a signal output end, and this negative input end is to be connected with the capacitor of oblique wave generation unit, and this positive input terminal is to be connected with an input signal.
2. a kind of mutually supplementary gain control circuit according to claim 1 is characterized in that, this current source is respectively equipped with a charging source and a discharge source.
3. a kind of mutually supplementary gain control circuit according to claim 1, it is characterized in that, this partial pressure unit is to connect with a supply voltage to establish, and divide to extrude high levle voltage and a low level voltage, the ramp voltage comparison of being imported for first comparing unit and oblique wave generation unit.
4. a kind of mutually supplementary gain control circuit according to claim 1 is characterized in that, this oblique wave generation unit is to produce ramp signal.
5. a kind of mutually supplementary gain control circuit according to claim 1 is characterized in that, this first comparing unit is the voltage difference with the high levle voltage and the low level voltage of partial pressure unit, to determine its oblique wave amplitude size.
6. a kind of mutually supplementary gain control circuit according to claim 3 is characterized in that, when this supply voltage descends, its power output or power gain promptly with decline.
7. a kind of mutually supplementary gain control circuit according to claim 3 is characterized in that, when this supply voltage descended, its duty ratio increased immediately.
8. a kind of mutually supplementary gain control circuit according to claim 5 is characterized in that, when this oblique wave amplitude rose, its duty ratio descended immediately; When this oblique wave amplitude descended, its duty ratio rose immediately.
9. a kind of mutually supplementary gain control circuit according to claim 8 is characterized in that, when this duty ratio rises, its power output or power gain promptly with rising.
10. a kind of mutually supplementary gain control circuit according to claim 9 is characterized in that, this power output is directly proportional with supply voltage and duty ratio.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100987606A CN100563097C (en) | 2006-07-12 | 2006-07-12 | Mutually supplementary gain control circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100987606A CN100563097C (en) | 2006-07-12 | 2006-07-12 | Mutually supplementary gain control circuit |
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| CN101106361A true CN101106361A (en) | 2008-01-16 |
| CN100563097C CN100563097C (en) | 2009-11-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100987606A Expired - Fee Related CN100563097C (en) | 2006-07-12 | 2006-07-12 | Mutually supplementary gain control circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101989843A (en) * | 2009-07-29 | 2011-03-23 | 凌阳科技股份有限公司 | Automatic gain control system having hysteresis switching |
| CN102025332A (en) * | 2009-09-18 | 2011-04-20 | 震一科技股份有限公司 | Gain control circuit and method |
| CN106411280A (en) * | 2015-07-28 | 2017-02-15 | 晶豪科技股份有限公司 | Power limitation amplifier |
| CN106411281A (en) * | 2015-07-31 | 2017-02-15 | 晶豪科技股份有限公司 | Power-limiting amplifier |
-
2006
- 2006-07-12 CN CNB2006100987606A patent/CN100563097C/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101989843A (en) * | 2009-07-29 | 2011-03-23 | 凌阳科技股份有限公司 | Automatic gain control system having hysteresis switching |
| CN101989843B (en) * | 2009-07-29 | 2013-10-30 | 凌阳科技股份有限公司 | Automatic gain control system having hysteresis switching |
| CN102025332A (en) * | 2009-09-18 | 2011-04-20 | 震一科技股份有限公司 | Gain control circuit and method |
| CN106411280A (en) * | 2015-07-28 | 2017-02-15 | 晶豪科技股份有限公司 | Power limitation amplifier |
| CN106411281A (en) * | 2015-07-31 | 2017-02-15 | 晶豪科技股份有限公司 | Power-limiting amplifier |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100563097C (en) | 2009-11-25 |
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Granted publication date: 20091125 Termination date: 20130712 |