main description

The S4512M chip is used with a high-voltage linear chip to drive the LED switch toning power supply. It controls the on and off of two LED light strings according to the action of the input switch, and has a state memory function, which can automatically store the state before turning off the lights, and Automatically renders the next time the light is turned on.

The S4512M adopts the patented technology of Xinfeiling Semiconductor, which can effectively solve the problems often encountered in the linear switch color temperature scheme: 1) The fast switch cannot be dimmed; 2) The peripheral circuit is complicated; 3) The state holding time is inconsistent.

The S4512M has two built-in 400V 1A thyristors, which can be used for current applications up to 260mA.

Features

Single quick switch reset function to solve the problem of asynchronous

With linear master chip

With state memory function

That is, the power can be constant and the power can be superimposed.

The logic state is stable when multiple power supplies are used at the same time

Switching effective hold time is externally adjustable

Patented technology, stable performance

Function Description

1. Power supply

As shown in Figure 1: The power supply pin VCC of S4512M is connected to the output positive pole of the rectifier bridge through the resistor R2, that is, the positive pole of the capacitor C1. Considering the highest AC voltage and the withstand voltage of the resistor, if the power supply resistor uses a patch Two resistors are recommended in series. Since the working current of the S4512M is about 200uA, the selection of the power supply current limiting resistor R2 must consider enough margin. The VDD of S4512M is the power supply pin of some internal circuits and registers, and an external capacitor is connected to it.

2. Built-in switch control

The S4512M has two built-in 400V switches, and the saturation conduction voltage of the switches is 1.2V. The S4512M is suitable for applications where the output current is less than 260mA. The pins G1 and G2 of the chip S4512M are connected to the control pins of the built-in switch tube. Since the chip only has the ability to pull down, the external pins G1 and G2 must be connected to the VCC pin of the chip through a pull-up resistor, as shown in Figure 1 and Figure 2. Show.

The two built-in switches of S4512 are thyristors, and the required maximum driving current is 200uA, so the current of G1 and G2 must be guaranteed to be greater than 200uA during design.

3. State Control

The S4512M has a built-in power-down storage unit, which can still save data for ten years without power. When the light is turned off, the S4512M will store the state before the light is turned off into the internal storage unit. When the light is turned on next time, the S4512M 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, S4512M will remember the user's favorite color temperature after turning off the light, and directly enter the user's favorite color temperature when the light is turned on next time. Although the S4512M 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 S4512M can still switch the color temperature through the input switch. If the user needs to switch the color temperature of the light, just turn the light back on within a few seconds after turning off the light, and the light will switch to the next state. When the lamp is turned on again, the color temperature of the lamp will switch to the next state, and in this cycle, the S4512M has a total of three states. As mentioned above, the S4512M is

There is a color temperature switching window for a few seconds after the light is turned off, 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. Generally, a VDD of 1uF The color temperature switching window corresponding to the capacitor is about 4S. When the light-off time exceeds the color temperature switching window and then it is turned on again, the state of the lamp is the color temperature state of the last time the light was turned off. Since the S4512M will remember the state before the last time the light was turned off, it will not be like a general color temperature control chip. After a period of time after the light is turned off, the internal state of the chip will return to the initial state, so when the state is inconsistent, you can turn off the light and If you turn on the lights for a long enough time, all the lights will return to the initial state, and the chip with memory cannot recover from power failure. After returning to the same state, the S4512M has a built-in quick reset function, that is, if the light is turned on again within 200ms after turning off the light, the S4512M will return to the initial state. To sum up, the state changes of S4512M are all based on the duration of the light-off. When the light-off time is within 200ms, the state returns to the initial state, and when the light-off time is within 200ms to 4S (the VDD capacitor is 1uF), the The state switches to the next state, and when the light-off time exceeds 4S, the state of the S4512M remains the state of the last time the light was turned off.

4. Application Notes

In the application of S4512M, the following principles must be followed:

1. The VDD capacitor should be placed as close as possible to the chip VDD and gnd pins.

2. The ground of the VCC capacitor and the chip ground should be as short as possible, and the VCC supply

Electric distance as short as possible

3. The heat dissipation of S4512M should be considered as much as possible in the PCB layout.

question