S4120M switch color temperature control chip with state memory

main description

S4120M is a switch color temperature control chip with state memory, that is, it can memorize the state before turning off the light. When the light is turned on next time, the lamp directly enters the state before the last time the light is turned off, which increases the convenience of use. S4120M can not only drive thyristors, but also drive MOS tubes. This series of chips adopts the patented technology of Xinfeiling, which can not only simplify the number of peripheral components to the greatest extent, but also ensure the logic consistency when multiple power supplies are applied at the same time. In order to expand the application field, the S4120M series can be used in the isolated flyback structure and the Buck structure, which provides convenience for the design of the power supply.

Features

@With state memory function, it is more convenient to use

@Quick reset function to solve the problem of asynchronous

@No problem of logical disorder when multiple power supplies are used at the same time

@Built-in voltage limiting circuit to ensure a wider working range

@Compatible with isolated and non-isolated applications

@Patented technology, stable performance

Scope of application

@Switch color temperature LED power supply

Function Description

1. Power supply

The S4120M is powered by the VCC pin. In the application, the VCC pin is connected to the positive pole of the power output through a current limiting resistor R2. Since the working current of the IC is about 0.8mA, there must be a margin in the design considering the factors affecting the working current such as temperature changes.

2. Detection

The detection pin of the chip is CLK. In the application, the CLK pin is connected to the end of the constant current power supply inductor and the positive electrode of the freewheeling diode through the detection resistor R1, as shown in the typical application diagram. The chip judges whether the input switch is closed or disconnected through the CLK pin. When the input switch is closed, the CLK pin detects the waveform of the square wave, and when the input switch is open, the square wave detected by the CLK pin disappears. In order to filter out noise and avoid false triggering, the S4120M has internally designed a delay time Td(on) for judging the closed state of the switch and a delay time Td(off) for judging the open state of the switch. The selection of the detection resistor R1 must ensure that the current flowing through R1 must be less than 2mA when the other end of the detection resistor has a negative voltage.

3. Drive

The S4120M series can be compatible with both thyristors and MOSFETs without any external changes, and the IC automatically recognizes the connected

type of switch tube. When driving the thyristor, the driving current is about 200uA. When driving MOS FET, the maximum output voltage of the driving pin is 5V. Since the maximum voltage of the driving pin of S4120M is 5V, when it is used to drive a MOSFET, a MOSFET with a lower threshold voltage must be selected.

4. Status control

The S4120M has a built-in power-down storage unit, which can still save data for ten years without power. When the S4120M turns off the light, it will store the state before turning off the light into the internal storage unit. When the light is turned on next time, the S4120M will directly retrieve the state in the storage unit as the output state, so the user does not need to switch to the internal storage unit every time the light is turned on. Favorite color temperature, because users only need to switch the color of the lamp to their favorite color temperature. After turning off the light, S4120M will remember the user's favorite color temperature, and directly enter the user's favorite color temperature when the light is turned on next time. Although the S4120M can remember the state of the last time the light was turned off, and directly enter the state of the last time the light was turned off the next time the light is turned on, the S4120M can still switch the color temperature through the input switch. like

If the user needs to switch the color temperature of the light, just turn the light on again within a few seconds after turning off the light, and the light will switch to the next state. When the light is turned on again, the color temperature of the light will switch to the next state. In this cycle, the S4120M has a total of three states. As mentioned above, the S4120M has a color temperature switching window for a few seconds after turning off the light, that is, if the light is turned on again within this window, the color temperature of the lamp will switch to the next state. The size of this color temperature switching window is determined by the size of the VDD capacitor. In general, the color temperature switching window corresponding to a 1uF VDD capacitor