TWI234924B - Linear-in-decibel variable gain amplifier - Google Patents

Abstract

A linear-in-decibel variable gain amplifier comprises: an amplifying stage, for generating an output voltage according to a differential input voltage; and a gain-controlling stage, for outputting a gain-controlling voltage to the amplifying stage according to a first controlling voltage and a second controlling voltage. A voltage gain of the linear-in-decibel variable gain amplifier is inverse proportional to a simple exponential function, and the value of the simple exponential function is determined by the difference between the first controlling voltage and the second controlling voltage. The value of the voltage gain is irrelevant to the change of the thermal voltage.

Description

1234924_ Brief description of the diagram Brief description of the diagram Figure 1 is a circuit diagram of a variable gain amplifier of the conventional technology. Figure 2 is a plot of the relationship between voltage gain and control voltage for Equation 1. FIG. 3 is a block diagram of an embodiment of an exponential gain type variable gain amplifier according to the present invention. FIG. 4 is a partial circuit diagram of an embodiment of the gain control circuit 304. FIG. 5 is a partial circuit diagram of an embodiment of the gain control circuit 304. Figure 6 is a graph of the relationship between the voltage gain and the first and second control voltages in accordance with Equation 11. FIG. 7 is a circuit diagram of an embodiment of a thermal voltage proportional voltage amplifier according to the present invention. Schematic symbol description

Page 19 300 Exponential gain variable gain amplifier 302 Amplifier stage circuit 304 Gain control circuit 400 Thermal voltage proportional voltage amplifier 401 Transduction unit 402 First current source 403 First current conversion unit 404 Second current source 405 Second current Conversion unit 407 Output unit 472 First transistor 473 Second transistor 474 Third transistor 475 Fourth transistor 476 Fifth transistor 477 Sixth transistor 1234924 Brief description of the drawing 478 Seventh transistor 479 苐 Eighth transistor 480 Ninth transistor 720 Transconductance amplifier unit 721 Operational amplifier 740 Current mirror unit 760 Transimpedance amplifier unit 761 Tenth transistor 762 Eleventh transistor ι ·· ι page 20

Claims (1)

mmM No. 92127224 _Ά Modification VI 1. Patent application range of variable gain amplifiers, including: an amplifier stage circuit to output an output voltage based on a differential input voltage; and a gain control circuit to The first control voltage and a second control voltage output a gain control voltage to the amplifier circuit, so that a voltage gain of one of the variable gain amplifiers is inversely proportional to a simple exponential function, and the value of the simple exponential function is determined by the first The difference between the control voltage and the second control voltage is determined, and the voltage gain is not affected by a thermal voltage. 2. The variable gain amplifier according to item 1 of the scope of patent application, wherein the amplifier stage circuit has a voltage gain, and its denominator is in the form of (Kl + exp (K2 X Vy)), where K1 is a constant, K2 is inversely proportional to the thermal voltage V y as the gain control voltage. 3. The variable gain amplifier according to item 1 of the patent application scope, wherein the gain control circuit includes: a thermal voltage proportional voltage amplifier for generating a third voltage according to the first control voltage and the second control voltage The control voltage and the fourth control voltage, wherein the difference between the third and fourth control voltages are respectively proportional to the difference between the first and second control voltages and the thermal voltage; a second transduction amplifier unit for: A third current and a fourth current are output according to the third control voltage and the fourth control voltage, wherein a ratio of the third current and the fourth current to the third control voltage and the first Page 21 x1234924; Case No. 92127224_year month and month revision_ VI. Patent application scope 4. The difference between the control voltages; a current conversion unit coupled to the second transconductance amplifier unit to output a fifth current, and The third current corresponds to a sixth current corresponding to the fourth current; and an output unit is coupled to the current conversion unit to output the gain control voltage according to the fifth current and the sixth current; The gain control voltage is determined by a difference between the first control voltage and the second control voltage. Among them, the equipment can be greatly increased and increased. One can be described as a series of 3J devices. The large fan can be used for profit and electricity. Please apply for positive pressure such as electricity. Including electricity, half of the road-controlled electricity is used for electricity, and electricity is used for the road; half yuan, two orders, the first one, and half-powered electricity are transferred to the guide. Combined with Yuan Yidan •, the big exile turned one first and the other! The color control controlled the third one. The voltage and voltage of the thermoelectric system should be controlled by the ratio of the positive and negative voltages. The electricity production test of the power generation electricity test has a surrounded elementary element Fan Shanli Diploma. Please refer to the application as described in the 5th. The first and the second are described; terminal pressure ^^ 6- the second control of the control system is the first and the first, the terminal is at the input and output coupling 43—the first input is at the first input and the first is at the first input. Loss of resistance ^ ¾ first and first and end of the second input device should be calculated at the combined end Page 22 n.,-I. “一 I |: 123 Lai ·, ϋ? ::: 丨 Case No. 92127224_Year Month and Amendment_ VI. Patent application output end, the other end is grounded; where the first current The first resistor flows through the first resistor. 6. The variable gain amplifier according to item 4 of the patent application scope, wherein the first half circuit further includes: a first current mirror unit coupled to the first transconductance amplifier. A unit for outputting a second current according to the first current. 7. The variable gain amplifier according to item 6 of the patent application scope, wherein the transimpedance amplifier unit includes: a first transistor whose base is coupled to the reference voltage; a second transistor whose collector Coupled to the first current mirror unit, the base of which is used to generate the third control voltage; a second current mirror unit coupled to the collector of the first transistor and the second transistor; and a first bias A piezo-current source is coupled to the emitters of the first transistor and the second transistor to provide a first bias current. 8. The variable gain amplifier according to item 7 in the scope of patent application, wherein the second current mirror unit includes: A third transistor whose drain and gate are coupled to the collector of the first transistor; and a fourth transistor whose drain is coupled to the collector of the second transistor and whose gate is coupled to the Gate of the third transistor. (Page 23) | Ι234349ΐ4: ·! Gy; current case number 92127224_ year, month, month, day, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, week, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month, month The third current is substantially equal, and the magnitude of the sixth current is substantially equal to the fourth current. 10. A thermal voltage proportional voltage amplifier, comprising: a transconductance amplifier unit; configured to output a first current according to a first input voltage; and A transimpedance amplifying unit is coupled to a reference voltage for generating a first output voltage according to the first current, wherein a difference between the first output voltage and the reference voltage is proportional to a thermal voltage. 1 1. The thermal voltage proportional voltage amplifier according to item 10 of the scope of patent application, wherein the transconductance amplifier unit includes: an operational amplifier having a first input terminal, a second input terminal and an output terminal, The first round-in terminal is coupled to the first input voltage; and a first resistor, one end of which is coupled to the second input terminal and the first end of the operational amplifier, and the other end of which is grounded; wherein the first current flows through the First resistance. 12. The thermal voltage proportional voltage amplifier according to item 10 of the scope of patent application, wherein the voltage amplifier further comprises: a first current mirror unit coupled to the transconductance amplifier unit, and Page 24 '·,', ^ ·: i, a K-— # 1234924, 1; Dance No. 92127224_year month and month amendment_ 6. The scope of the patent application The first current outputs a second current. 1 3. The thermal voltage proportional voltage amplifier according to item 12 of the patent application scope, wherein the transimpedance amplifier unit includes: a first transistor whose base is coupled to the reference voltage; a second transistor whose collector is coupled A base of the first current mirror unit is used to generate the first output voltage; a second current mirror unit is coupled to a collector of the first transistor and the second transistor; and A first bias current source is coupled to the emitter of the first transistor and the second transistor to provide a first bias current. 14. The thermal voltage proportional voltage amplifier according to item 13 of the scope of the patent application, wherein the second current mirror unit includes: a third transistor whose drain and gate are coupled to the first transistor. A collector; and a fourth transistor whose drain is coupled to the collector of the second transistor and whose gate is coupled to the gate of the third transistor. 15. The thermal voltage proportional voltage amplifier as described in item 10 of the scope of patent application, wherein the thermal voltage proportional voltage amplifier is a half circuit of a differential amplifier. Page 25