The AT9932 is an advanced fixed frequency PWM controller IC designed to control an LED lamp driver using a boost-buck topology that can step the input voltage up or down automatically. The IC provides fast output current transient response and very low susceptibility to input voltage transients, which allows the lamp driver to pass the rigorous electrical transient requirements of SAE J1455 or ISO 7637-2, making the AT9932 an ultimate solution for automobile lighting. Capacitive isolation protects the LED Lamp from failure of the switching MOSFET.
The AT9932 features a unique feed-forward current control scheme, differential output current sensing, soft start, protection from short or open LED load. Switching frequency can be programmed with a single external resistor. The AT9932 includes a temperature fold-back of the output current using an external NTC resistor. This feature allows maximizing the light output of the LED load over the entire operating temperature range.
AT9932主要特性：
Constant output current
Steps output voltage up or down
Very low susceptibility to Input voltage transients
Frequency jitter
Externally programmable fixed switching frequency
Temperature foldback with external NTC resistor
Internal 40V voltage regulator
+/-1A MOSFET gate driver
Short LED protection
Open LED protection
Input undervoltage protection
Enable & PWM dimming
Trimmed reference (±3% accurate)
AEC-Q100 compliant
AT9932应用：
Automobile lighting
Battery powered LED lamps
Other low voltage AC/DC or DC/DC LED drivers
图1。AT9932功能方框图
图2。AT9932典型应用电路图
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