The setting of channel current for SiLM4228x (x=0, 1, 2, 3) is as follows:
1. Divide 1.5V by the resistance of IRx (x=1, 2, 3) pins to obtain a current;
2. Multiply the current obtained above by 960 times to obtain the corresponding channel current
The single lamp short circuit threshold calculated based on the Datasheet refers to the protection when the LED terminal voltage is below this threshold. The function of this protection is to prevent LED damage and short circuit during practical application, resulting in a decrease in the voltage at the LED end. At this time, there will be high power consumption on the chip, and this protection is to protect the chip from overheating.
Isolation drive is a drive product that uses isolation technology to electrically isolate the control signal on the low voltage side and the drive signal on the high voltage side. Shuming's isolation drive products adopt capacitive isolation technology.
In a half bridge circuit, the driving voltage of the upper transistor is generally achieved through a bootstrap circuit. When the lower tube is turned on, the power supply charges the bootstrap capacitor through the path of bootstrap diode, bootstrap capacitor, and lower tube. When the upper tube is turned on, the voltage on the bootstrap capacitor provides voltage to the driver of the upper tube. In a half bridge circuit powered by a bootstrap circuit, the lower transistor must have a certain opening time to ensure that the voltage on the bootstrap capacitor is sufficient to open the upper transistor.
The driver isolation module is mainly used to isolate the signal from the power circuit to prevent signal crosstalk, and can also provide protection against short circuits, overvoltage, undervoltage, overcurrent, etc., to prevent damage to the entire circuit when a problem occurs at a certain location
1. Select the appropriate PWM channel for the half bridge output (HB-MODE.CTRL)
2. Select the appropriate duty cycle (PWP_DC_CTRL)
3. Turn on the PWM working mode of half bridge output (fw_ctrl), and the A3 board will not need to write this register in the future. The default value is 00
4. Choose a suitable working frequency for PWM (80Hz-2kHz, PWP_Ch-Freq.Ctr, ovp2_2k_ctrl)
5. Enable corresponding channel (HB_ACT_CTRL)
SiLM4228x (x=0123) has identical parameters except for the Open diagnostic enable threshold
