CN103731124B - A kind of ladder wave generation circuit - Google Patents

Abstract

The invention relates to electronic circuit technology, in particular to a ladder wave generating circuit. The rectifier bridge circuit of the present invention is characterized in that it also includes a plurality of ladder voltage regulation networks and a plurality of constant current control networks, the rectifier bridge circuit is connected with the ladder voltage regulation network and the constant current control network, and the ladder voltage regulation The number of network and constant current control network is equal to one corresponding connection. The beneficial effect of the invention is that it can generate a ladder wave with any order and adjustable step voltage, and at the same time, the circuit structure is simple, there is no digital logic control, and no programming is required, which can effectively improve the utilization efficiency of the circuit. The invention is especially suitable for a ladder wave generating circuit.

Description

A ladder wave generating circuit

technical field

The invention relates to electronic circuit technology, in particular to a ladder wave generating circuit.

Background technique

At present, in the field of electronic circuit design, the staircase wave is a commonly used analog signal. The traditional ladder wave generator generally has the following two schemes: the first scheme is shown in Figure 1, including a square wave generator, a differential circuit, a limiter circuit, an integral accumulation circuit, an electronic switch circuit, a comparator and an oscillation circuit. , the principle is to generate a square wave through a square wave generating circuit, and then through a differential circuit to obtain a waveform with sharp pulses up and down. At this time, to only take the sharp pulse above, it is necessary to filter out the lower half of the waveform through the limiter circuit. When these pulses pass through the integration and accumulation circuit, a sharp pulse is accumulated to a fixed value, and the same value will be increased when the next pulse arrives, so the output forms a staircase waveform. When the accumulation result does not exceed the threshold of the comparator, it will continue to accumulate. When the threshold is reached, the output voltage of the comparator is reversed, and the positive voltage is output to make the oscillation control circuit work, so that the square wave stops vibrating, and at the same time, the integral capacitor is short-circuited and discharged to the ground, and the capacitor returns to the initial state and the accumulation ends. After the capacitor is discharged, the output of the integrator jumps from a negative value to zero, causing the comparator to flip again, the oscillation circuit cannot work, the output of the comparator becomes negative, and the whole circuit will normally generate a staircase wave, and so on. cycle. It can be seen that this solution is implemented by integrated operational amplifiers or transistors. Although it is simple, it has obvious disadvantages: it is very difficult to generate a ladder wave whose levels can be adjusted at will, and all circuits such as the square wave generator and comparator must be rebuilt Setting and adjustment will cause the circuit structure to become complicated. The second scheme is shown in Figure 2, including a clock signal generator, a counter, a CPU, and a digital-to-analog converter. It is mainly realized through the control of a programmable device to generate a ladder wave. Compared with the first scheme, this scheme can be obtained Flexible and changeable waveforms, but this solution requires programming, which limits its application occasions. On the other hand, the high cost of a high-speed processor further limits its application.

Contents of the invention

What the present invention aims to solve is to propose a ladder wave generating circuit with a simple circuit structure and no need for programming, aiming at the problems existing in the above-mentioned traditional ladder wave generating circuit.

The technical solution adopted by the present invention to solve the above technical problems, as shown in Figure 3, includes a rectifier bridge circuit, and is characterized in that it also includes a plurality of ladder voltage regulation networks and a plurality of constant current control networks, the rectifier bridge circuit and the ladder The voltage regulation network is connected to the constant current control network, and the number of the ladder voltage regulation network and the constant current control network are equal and connected in sequence; wherein,

The rectifier bridge circuit is used to provide direct current for the ladder voltage regulation network and the constant current control network;

Under the control of the constant current control network, the ladder voltage regulation network outputs ladder radio waves with arbitrary order and adjustable ladder voltage.

As shown in Figure 4, the constant current control network includes a reference voltage source unit, a current sampling unit, an operational amplifier and an adjustment tube; the current sampling unit is connected to a ladder voltage regulation network, and the reference voltage source unit and the current sampling unit The input terminal of the operational amplifier is connected, and the output terminal of the operational amplifier is connected with an adjustment tube, and the adjustment tube is connected with a ladder voltage regulation network; wherein,

The reference voltage unit is used to generate a constant reference voltage, which is input to an input terminal of the operational amplifier;

The current sampling unit is used to adjust the current of the ladder voltage network, and feed back the input to the other input terminal of the operational amplifier in the form of voltage;

The operational amplifier is used to receive the reference voltage and sampling voltage, and output the voltage control signal to the adjustment tube;

The adjustment tube adjusts the current of the ladder voltage regulation network according to the control signal of the operational amplifier, and keeps the current of the ladder voltage regulation network constant.

The beneficial effect of the invention is that it can generate a ladder wave with any order and adjustable step voltage, and at the same time, the circuit structure is simple, there is no digital logic control, and no programming is required, which can effectively improve the utilization efficiency of the circuit.

Description of drawings

Fig. 1 is the schematic block diagram of the first traditional ladder wave circuit;

Fig. 2 is the block diagram of the second conventional ladder wave circuit;

Fig. 3 is a block diagram of the ladder wave circuit principle of the present invention;

Fig. 4 is a more specific functional block diagram of the ladder wave circuit of the present invention;

Fig. 5 is the schematic diagram of the circuit structure of embodiment;

Fig. 6 is a schematic diagram of the ladder wave generated by the embodiment.

detailed description

Below in conjunction with accompanying drawing and embodiment, describe technical solution of the present invention in detail:

The capacitive step-down circuit of the present invention, as shown in Figure 3, includes a rectifier bridge circuit, and is characterized in that it also includes a plurality of ladder voltage regulation networks and a plurality of constant current control networks, the rectifier bridge circuit and the ladder voltage regulation network and The constant current control network is connected, and the number of the ladder voltage regulation network and the constant current control network are equal and connected in sequence; wherein,

The rectifier bridge circuit is used to provide direct current for the ladder voltage regulation network and the constant current control network;

Under the control of the constant current control network, the ladder voltage regulation network outputs ladder radio waves with arbitrary order and adjustable ladder voltage.

As shown in Figure 4, the constant current control network includes a reference voltage source unit, a current sampling unit, an operational amplifier and an adjustment tube; the current sampling unit is connected to a ladder voltage regulation network, and the reference voltage source unit and the current sampling unit The input terminal of the operational amplifier is connected, and the output terminal of the operational amplifier is connected with an adjustment tube, and the adjustment tube is connected with a ladder voltage regulation network; wherein,

The reference voltage unit is used to generate a constant reference voltage, which is input to an input terminal of the operational amplifier;

The current sampling unit is used to adjust the current of the ladder voltage network, and feed back the input to the other input terminal of the operational amplifier in the form of voltage;

The operational amplifier is used to receive the reference voltage and sampling voltage, and output the voltage control signal to the adjustment tube;

The adjustment tube adjusts the current of the ladder voltage regulation network according to the control signal of the operational amplifier, and keeps the current of the ladder voltage regulation network constant.

Example:

As shown in Figure 5, the AC sine wave AC is rectified by the rectifier bridge and becomes a steamed bun wave. When the voltage is zero, the m ladder voltage regulation network has no current, the current flowing through the sampling resistor Rs is zero, the voltage on the sampling resistor is zero, and the voltage fed back to the negative input terminals of the m operational amplifiers is zero, and the output of the operational amplifier is zero. Forward saturation voltage, the m MOS transistors M1M2...Mm are fully turned on. When the voltage rises to the voltage at which the N1 diodes of the first ladder voltage regulation network are turned on, the first ladder voltage regulation network is turned on, and a current flows through the sampling resistor. The voltage continues to increase, and the current increases. Due to the clamping effect of the op amp, the current is constant at VREF_1/Rs. The ladder output voltage is:

V=N1*Vt+R1*VREF_l/Rs

Vt is the forward conduction voltage drop of the diode.

The input voltage continues to increase, and a smaller current is generated in the second ladder voltage regulation network, so that the voltage on the sampling resistor increases and is greater than VREF_1. The output of the first constant current control operational amplifier is low level, and the MOS transistor M1 is cut off. The current passes through the first ladder voltage regulation network, the second ladder voltage regulation network, the second constant current control network, and RS to ground. The sampling current is VREF_2/Rs. The ladder output voltage is:

V＝N1*Vt+R1*VREF_2/Rs

Vt is the forward conduction voltage drop of the diode.

The principle is the same as above, N step voltage regulation networks can generate step waves of N step voltages, and different step waves can be obtained by setting the amplitude and frequency of the input sine wave and the number of diodes and resistances in each step voltage regulation network.

Fig. 6 is the ladder wave graph of the embodiment of the present invention, the dotted line is the sine wave rectified by the rectifier bridge, the solid line is the ladder wave waveform generated by the embodiment, the specific ladder voltage can be set by the ladder voltage mediation network, and the number of steps can be set by the ladder Voltage regulation network settings.

Therefore, the ladder wave generation circuit realized by the technical solution of the present invention has the following beneficial effects: the ladder voltage can be of any order, and the ladder voltage is adjustable; the circuit is simple, there is no digital logic control, and no programming is required; it can be directly Connecting to commercial power for transformation; in signal source devices such as function generators, the solution of the present invention has unique advantages, and can be constructed by using existing circuits to improve circuit utilization efficiency.

Claims (1)

1. A ladder wave generation circuit, comprising a rectifier bridge circuit, is characterized in that, also includes a plurality of ladder voltage regulation networks and a plurality of constant current control networks, and the rectifier bridge circuit is connected with the ladder voltage regulation network and the constant current control network , the number of the ladder voltage regulation network and the constant current control network are equal and connected in sequence; wherein, The rectifier bridge circuit is used to provide direct current for the ladder voltage regulation network and the constant current control network; Under the control of the constant current control network, the ladder voltage regulation network outputs ladder waves with any order and adjustable ladder voltage; The constant current control network includes a reference voltage source unit, a current sampling unit, an operational amplifier and an adjustment tube; the current sampling unit is connected to a ladder voltage regulation network, and the reference voltage source unit and the current sampling unit are connected to the input of the operational amplifier , the output terminal of the operational amplifier is connected to the adjustment tube, and the adjustment tube is connected to the ladder voltage regulation network; wherein, The reference voltage unit is used to generate a constant reference voltage, which is input to an input terminal of the operational amplifier; The current sampling unit is used to adjust the current of the ladder voltage network, and feed back the input to the other input terminal of the operational amplifier in the form of voltage; The operational amplifier is used to receive the reference voltage and sampling voltage, and output the voltage control signal to the adjustment tube; The adjustment tube adjusts the current of the ladder voltage regulation network according to the control signal of the operational amplifier, and keeps the current of the ladder voltage regulation network constant.