description:
The typical application circuit of the TOPSwitch series monolithic switching power supply is shown in the figure. The high-frequency transformer has three functions of energy storage, isolated output and voltage conversion in the circuit. It can be seen from the figure that the polarity of the primary winding Np of the high-frequency transformer (represented by a dot at the same name) is exactly opposite to the polarity of the secondary winding Ns and the feedback winding NF. This means that when the TOPSwitch is turned on, the electrical energy is stored in the primary winding as magnetic field energy, at which point VD2 is turned off. When TOPSwitch is turned off, VD2 is turned on and energy is transferred to the secondary. This is the characteristic of the flyback switching power supply. In the figure, BR is the rectifier bridge and Cin is the input filter capacitor. The AC voltage u is rectified and filtered to obtain a DC high voltage V1, which is applied to the drain of the TOPSwitch via the primary winding. In view of the TOPSwitch turn-off time, the peak voltage generated by the high-frequency transformer leakage inductance is superimposed on the DC high voltage V1 and the induced voltage Vor, so that the drain voltage of the power switch tube exceeds 700V and damage the chip; The drain clamp protection circuit must be added at both ends. The clamp circuit consists of a transient voltage suppressor or Zener diode (VDz1) and a blocking diode (VD1). The VD1 should use an ultra-fast recovery diode (SRD). VD2 is the secondary rectifier and Cout is the output filter capacitor.
The power supply uses an optocoupler feedback circuit with a Zener diode. The feedback winding voltage is rectified and filtered by VD3 and Cf to obtain the feedback voltage Vfb, and the phototransistor in the optocoupler is supplied with a bias voltage to the control terminal of the TOPSwitch. CT is the bypass capacitor of control terminal C. Set the steady voltage of the voltage regulator VDz2 to Vz2, the voltage drop across the resistor of the current limiting resistor R1 is Vr, the forward voltage drop of the LED light-emitting diode in the optocoupler is VF, and the output voltage VO is set by:
VO=Vz2+VF+Vr
The voltage regulation principle of the power supply is briefly described as follows: When VO rises due to some reason (such as an increase in AC voltage or a light load), since VZ2 does not change, VF rises accordingly, and the operating current of the LED is increased. The IF is increased, and the control terminal current IC of the TOP-Switch is increased by the optical coupler. However, because the output duty ratio D of TOPSwitch is inversely proportional to IC, D is reduced, which forces VO to decrease and achieve regulation. On the contrary, VO↓→VF↓→IF↓→IC↓→D↑→VO↑ also acts as a voltage regulator. It can be seen that the feedback circuit adjusts the duty cycle of the TOPSwitch to stabilize the output voltage.
Single-chip switching power supply typical application circuit
ZGAR electronic cigarette uses high-tech R&D, food grade disposable pod device and high-quality raw material. All package designs are Original IP. Our designer team is from Hong Kong. We have very high requirements for product quality, flavors taste and packaging design. The E-liquid is imported, materials are food grade, and assembly plant is medical-grade dust-free workshops.
From production to packaging, the whole system of tracking, efficient and orderly process, achieving daily efficient output. WEIKA pays attention to the details of each process control. The first class dust-free production workshop has passed the GMP food and drug production standard certification, ensuring quality and safety. We choose the products with a traceability system, which can not only effectively track and trace all kinds of data, but also ensure good product quality.
We offer best price, high quality Pods, Pods Touch Screen, Empty Pod System, Pod Vape, Disposable Pod device, E-cigar, Vape Pods to all over the world.
Much Better Vaping Experience!
Pods, Vape Pods, Empty Pod System Vape,Disposable Pod Vape Systems, MAX ICE
Shenzhen WeiKa Technology Co.,Ltd. , https://www.oemvape-pen.com