A power supply circuit with emitter current negative feedback

Abstract

The present invention designs a "power supply circuit with emitter current negative feedback" to solve the problem that the current voltage-stabilized power supply has a slow reaction speed to follow the lower load, and the technical solution to solve the problem is to change the differential connection large loop voltage negative feedback in the original power supply circuit to a large loop current negative feedback composed of Q5, Q6, R5, and R6 common base connection, so that the speed and frequency of the large loop current negative feedback from the R7 loop connected to the Vo terminal to the base terminal of Q7 can be greatly improved, solving the problems of time delay in the large loop negative feedback process and the problems of slow power supply tracking speed and low output frequency, and can also be integrated in a three-terminal voltage stabilizing block to reduce the volume. It belongs to analog electronic technology and is mainly used in the field of high-speed power supply.

Description

Technical Field

[0001] The present invention relates to a common-base conversion circuit with emitter negative feedback, which belongs to analog electronic technology and is mainly used in power supply circuits requiring high-speed transmission, and in particular to a circuit that uses common-base inverting input stage negative feedback to replace common-emitter differential inverting input stage negative feedback.

[0002] It belongs to analog electronic technology and is mainly used in the field of high-speed power supply. Background Art

[0003] The power supply is an indispensable circuit for providing energy to the circuit. At present, in the digital age, circuits are developing towards high frequency and high speed. The analog power supply circuit connected to the power supply of the digital circuit in the past, whether it is a three-terminal voltage-stabilized power supply or a power supply circuit composed of discrete components, can no longer adapt to the development of the current era. In the analog power supply circuit, the differential inverting input amplifier circuit is the first to bear the brunt. It is the bottleneck that determines whether the load power supply can develop towards high frequency and high speed. This circuit is designed with this as the starting point to replace the voltage negative feedback of the common emitter differential inverting input stage with the current negative feedback of the common base inverting input stage. A circuit is used to replace the current differential circuit composed of the common emitter circuit, and it can also be made into a three-terminal voltage regulator block to reduce the volume. Summary of the invention

[0004] In order to overcome the problem of low operating frequency of the differential circuit composed of the common emitter circuit and slow transmission speed during large loop negative feedback, the present invention designs a current negative feedback circuit composed of a common base circuit to replace the original common emitter differential voltage negative feedback circuit. We know that the actual operating frequency of the transistor in the common emitter connection is only f C =f T / h fe , and in the common base connection method, its operating frequency can be close to f T It can be seen that the operating frequency of the common base connection method is increased by h compared with the common emitter connection method. fe times, which is the purpose of using common base instead of common emitter in this circuit.

[0005] The power supply circuit of the emitter current negative feedback of the present invention solves its technical problem by adopting the technical solution: in order to realize the large-loop current negative feedback, Q5 and Q6 are designed to be in a common base form and R5 and R6 are connected at their emitters, and the dynamic and static currents of R5 and R6 are controlled by the U1 voltage regulator tube LM317LZ (the tube is T092 packaged and has a compact shape. The most attractive feature is its high voltage stabilization performance and low temperature drift far exceeding that of ordinary voltage regulator tubes, as well as its low price, making it more practical than ordinary voltage regulator tubes), and then R7 is connected to realize the current large-loop negative feedback. In order to enable the lower-level load to obtain current faster and more timely, the circuit is designed as a power supply circuit consisting of Q1, R1, Q7, and Q8.

[0006] The emitter current negative feedback power supply circuit of the above invention has the following working principle: the unregulated power supply is input by Vi. At this time, since the quiescent current of U1 is less than 6mA, it keeps the Vbe of Q1 always turned on. At this time, the value of R1 will determine the current of the power supply circuit. At the same time, since the collector AC impedance of Q1 is very large, the Vin of U1 can obtain a relatively flat DC current, which provides a guarantee for the smooth DC reference voltage output by Vout of U1. When the current flows through the emitter of Q2 and enters the collector to reach Vo, R7 and R5 form a sampling circuit. The value of R7 can be adjusted to calibrate the voltage value of Vo. When a positive temperature drift occurs at the Vo terminal, the current flowing into R7 and R5 increases, and the currents of R3 and R4 decrease proportionally. Since IR6 is a constant reference current during design, the decrease in R4 current will inevitably lead to an increase in Qb7 current, causing Qe8 current to increase and Vo voltage to drop to a preset value. When a negative temperature drift occurs, the current flowing into R7 and R5 decreases, and the currents of R3 and R4 increase proportionally. Since IR6 is a constant reference current during design, the increase in R4 current will inevitably lead to a decrease in Qb7 current, causing Qe8 current to decrease and Vo voltage to rise to a preset value.

[0007] The beneficial effect of the large-loop current negative feedback adopted in the present invention is that because the power supply circuit changes the differential connection into a large-loop current negative feedback composed of a common-base connection, the speed and frequency of the large-loop negative feedback from the Vo terminal to the Qb7 terminal are greatly improved, thereby solving the problem of time delay generated in the large-loop negative feedback process and the problems of slow power supply tracking speed and low output frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawing is a circuit structure diagram of a specific embodiment of a power supply circuit with emitter current negative feedback of the present invention.

[0009] Specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION

[0010] This circuit uses Vi in the attached figure as the input terminal, and its circuit connection method is: Vi→Q1 emitter, collector→Vin terminal of U1 (ADJ grounded)→Vout terminal→R2 (the other end is grounded)→Q5, Q6 base, Vi→R1→Q2 emitter, collector→R3→Q3 emitter, collector (collector→Q3, Q4 base)→Q5 collector, emitter→R5→ground, Q2 collector→R4→Q4 emitter, collector→Q7 base→Q6 collector, emitter→R6→ground, Q2 collector→Q8 emitter, collector→ground, Q8 base→Q7 emitter, collector→ground, Q2 collector→R7→R5 upper end. Q2 collector→Vo terminal.

Claims

1. "A power supply circuit with emitter current negative feedback" Features: The Vi end is electrically connected to one end of the resistor R1, one end of the resistor R1 is electrically connected to the emitter of the switch tube Q1, the other end of the resistor R1 is electrically connected to the base of the switch tube Q1, the collector of the switch tube Q1 is electrically connected to the Vin end of the three-terminal voltage regulator U1, the emitter of the switch tube Q2 is electrically connected to the base of the switch tube Q1, the base of the switch tube Q2 is electrically connected to the collector of the switch tube Q1, the collector of the switch tube Q2 is electrically connected to one end of the resistor R3, i.e., the Vo end, the other end of the resistor R3 is electrically connected to the emitter of the switch tube Q3, the base of the switch tube Q3 is short-circuited with the base of Q4, the base of the switch tube Q3 is short-circuited with the collector of Q3, the collector of the switch tube Q3 is electrically connected to the collector of the switch tube Q5, the base of the switch tube Q5 is short-circuited with the base of the switch tube Q6, the emitter of the switch tube Q5 is electrically connected to one end of the resistor R5, the other end of the resistor R5 is electrically connected to the ground, and the One end of the resistor R4 is electrically connected to Vo, the other end of the resistor R4 is electrically connected to the emitter of the switching tube Q4, the collector of the switching tube Q4 is electrically connected to the collector of the switching tube Q6, the emitter of the switching tube Q6 is electrically connected to one end of the resistor R6, the other end of the resistor R6 is electrically connected to the ground, one end of the ADJ of the three-terminal voltage regulator U1 is electrically connected to the ground, the Vout end of the three-terminal voltage regulator U1 is electrically connected to one end of the resistor R2, the other end of the resistor R2 is electrically connected to the ground, the Vout end of the three-terminal voltage regulator U1 is electrically connected to the bases of the switching tubes Q5 and Q6, the base of the switching tube Q7 is electrically connected to the collector of the switching tube Q4, the emitter of the switching tube Q7 is electrically connected to the base of the switching tube Q8, the emitter of the switching tube Q8 is electrically connected to the Vo end, the collectors of the switching tubes Q7 and Q8 are electrically connected to the ground, one end of the resistor R7 is electrically connected to the Vo end, and the other end of the resistor R7 is electrically connected to the emitter of the switching tube Q5.

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