Linear voltage stabilizing circuit is found in many products, and it is a common voltage stabilizing circuit product. The general linear voltage stabilizing integrated circuit consists of rectifier circuit, filter circuit and voltage stabilizing circuit. Its working principle is that the AC signal of the input power supply is converted into a DC signal after being stepped down and rectified by the transformer, and then the AC component is removed by the filter circuit, and finally it is stabilized at the target output voltage by the voltage stabilizing circuit, so as to provide a constant voltage for the product. In this issue, Hottech recommended a three-terminal voltage regulator product 78M06, which is widely used in switching power supply and other products.

Characteristics of 78M06

The output voltage range of this product is 5.75~6.25V, the maximum output current is 500mA, the maximum input voltage is 35V, the static current is 6mA, and the dissipation power is 1250mW. The 78M06 product has the characteristics of high reliability, good voltage stability, good product stability and excellent conductivity.

The 78M06 produced by Hottech adopts TO-252 machine surface mount form. This product has the advantages of easy welding, small volume, light weight (about 0.055g) and good heat dissipation performance, and can be applied to circuits with high power or high voltage, and can withstand high current and power.

Application of 78M06

Hottech's 78M06 product is produced by Dongguan factory. The product has been verified by many customers, and it is stable and practical. It can be used in power module, inverter, voltage regulator, DC motor drive, power converter, telephone, inverter, LED, communication transmitter, power tools and other applications. This paper mainly introduces several very common application scenarios of 78M06 products, so that everyone can better understand the role of 78M06.

1. Linear voltage regulator

The function of this product is to keep the voltage stable, and the resistance of the regulator will respond to the changes of load and input voltage to achieve the stable output voltage. Its action is just like a variable resistor that constantly adjusts its resistance value to keep it fixed with the partial pressure obtained by the load, while the extra energy due to the difference between output and input voltage is dissipated in the form of heat. On the other hand, the switching regulator is constantly switching on/off at high speed, so that the average output value is kept at the required voltage value. The voltage input to the linear regulator must be higher than the output voltage, so that the regulator can reduce the voltage to achieve stable output, so the efficiency is limited.

The linear regulator can be placed between the power supply and the load (series regulator) or connected in parallel with the load (parallel regulator). Because linear regulators are widely used, they are mostly made into integrated circuits. 78M06 product is a very common voltage regulator product, which is widely used.

2. Constant current regulator

Constant-current switching regulator is an electronic product with powerful function, stable performance, safety and reliability, and wide application. It can make the output current of electronic circuit unaffected by input and output voltage, ensure that the average current of products working in constant off-time mode is stable without peak-to-average error, and improve the stability of the circuit. It can be widely used in LED lighting equipment, dimming power supply, car headlights and fluorescent lamps, and its main function is to provide constant current driving ability for LEDs. It is also accurate and stable. Hottech's 78M06 integrated circuit is stable and has high performance reliability, which plays a very important role in improving the stability of circuit output current.

3. Voltage follower

As a voltage feedback circuit, the voltage follower has the same output voltage as the input voltage, but it improves the load capacity, and is usually used in buffer and isolation circuits. Voltage follower is generally used as buffer stage and isolation stage, because the output impedance of voltage amplifier is generally high. If the input impedance of the latter stage is relatively small, then a considerable part of the signal will be lost in the output resistance of the former stage. At this time, the voltage follower is needed to buffer it and play a connecting role. Another advantage of applying voltage follower is to improve the input impedance, so that the capacity of input capacitor can be greatly reduced, which provides a prerequisite for applying high-quality capacitor.

Another function of voltage follower is isolation. In HI-FI circuit, many amplifier circuits can't work well without negative feedback. However, due to the introduction of large-loop negative feedback circuit, the back electromotive force of the speaker will be superimposed with the input signal through the feedback circuit, resulting in blurred sound quality and reduced clarity. Some final stages of power amplifiers adopt circuits without large-loop negative feedback, and its distortion is difficult to guarantee because the working current of the final stage of the amplifier changes greatly. The function of voltage follower can achieve a very good effect, making the output voltage equal to the input voltage. Putting the circuit between the front stage and the power amplifier can cut off the interference of the back electromotive force of the speaker to the front stage and greatly improve the clarity of sound quality.

4, amplitude modulator

Amplitude modulator is a circuit that means that the amplitude of the modulated wave changes with the modulated signal. Amplitude modulator used in high-power broadcast or communication transmitter requires sufficient output power and high efficiency. Amplitude modulator is mainly composed of nonlinear devices and selective circuits. Nonlinear devices realize frequency conversion and produce sideband and harmonic components; The selective circuit is used to select the required frequency components and filter out other components, such as higher harmonics. Commonly used nonlinear devices include crystal diodes and field effect transistors, and most selective circuits use resonant circuits or bandpass filters.

Generally, amplitude modulators can be divided into high-level amplitude modulation and low-level amplitude modulation according to the level. High-level amplitude modulators are mostly used in high-power amplitude modulation transmitters, which have high output power and high efficiency. Carrier telephones and various electronic instruments mostly use low-level amplitude modulators, which do not require high output power and efficiency, so circuits with good amplitude modulation characteristics can be selected.

The above are several typical application cases of Hottech product 78M06 integrated circuit in the client. These applications have been verified for a long time, the product is stable and reliable, and the application scenarios have been verified many times. In addition, 78M06 can also be used in voltage stabilizing circuit, temperature compensation circuit, high current regulator, voltage regulator and current limiting protection circuit at power output. In the practical application of 78M06, engineers choose the most suitable chip according to the scene, product parameters and application requirements to give full play to the best performance of the circuit.