A6265
Automotive High Current LED Controller
Functional Description
The A6265 is a DC-DC converter controller that is designed to
drive series-connected high power LEDs in automotive applica-
tions. It provides programmable constant current output at load
voltages and currents limited only by the external components.
For automotive applications optimum performance is achieved
when driving between two and ten LEDs at currents up to 1 A.
source of the PMOS FET used to isolate the load from the supply.
Table 1 defines when FF1 is active. If FF1 is pulled low when
an output short fault is indicated then the output disable will be
overridden.
FF2 Fault Flag output. Open drain output, when high impedance
indicates detection of a circuit fault. An external pull-up resistor
should be connected to a suitable logic supply. If VREG is not
used, then the logic supply should not be pulled 300 mV above
The A6265 can be configured as a standard boost converter or
as a supply referenced boost converter. In the supply referenced
configuration the load voltage is the difference between the boost VREG. Table 1 defines when FF2 is active. If FF2 is pulled low
voltage and the supply voltage. This difference can be greater
than, equal to, or less than the supply voltage, effectively provid-
ing a buck-boost capability. This configuration provides seam-
less, uninterrupted operation over the wide supply voltage range
possible in automotive applications and, because the output is ref-
erenced to the positive supply, there is no load current to ground.
This ensures that there is no leakage path through the LEDs when
in shutdown and no inrush current at power-up.
when an open LED fault is indicated then the output disable will
be overridden.
OSC Resistor to ground to set the internal oscillator or clock
input from external oscillator. When connected to VREG the
oscillator runs at typically 350 kHz. Higher accuracy in the
frequency is possible by connecting a resistor from this pin to
ground or by driving this pin with an external precision oscillator.
CKOUT Logic output at the oscillator frequency with phase
shift. Used to drive succeeding controllers to interleave switching
instants.
The A6265 integrates all necessary control elements to pro-
vide a cost-effective solution using a single external logic-level
MOSFET and minimum additional external passive components.
IREF LED current reference modifier. A voltage input that can be
used to reduce the LED current sense voltage. When connected to
VREG, the current sense voltage, VIDL, and the value of the sense
resistor, RSL, define the maximum LED current.
The LED current is set by selecting an appropriate value for the
sense resistor value and using the EN input to provide simple
on-off control or for PWM brightness control using a suitable
externally generated PWM signal. The LED current can be
reduced in a single step by reducing the voltage between the
IREF pin and GND to less than 1 V.
SG Gate drive for external logic-level MOSFET low-side switch
that connects the inductor to ground.
The pin functions and circuit operation are described in detail in
the following sections.
SP, SN Sense amplifier connections for switch current limit
sense resistor, RSS
.
Pin Functions
VIN Supply to the control circuit. A bypass capacitor must be
connected between this pin and GND.
LP Positive sense amplifier connection for LED current limit
sense resistor, RSL. This pin is also the bias supply for the LED
current sense amplifier.
GND Ground reference connection. This pin should be connected LN Negative sense amplifier connection for LED current limit
directly to the negative supply.
sense resistor, RSL. The voltage at LN also determines whether
the boost or buck-boost mode is configured.
EN Logic input to enable operation. Can be used as direct PWM
input. Chip enters low power sleep mode when low for longer
VREG Compensation capacitor for internal 5 V regulator.
than the disable time, tDIS
.
LA Anode reference connection to LEDs. Using an external resis-
FF1 Fault Flag output and isolation control. Open drain current
tor divider with the same ratio as the number of LEDs provides
sink output, when high impedance indicates detection of a critical a measurement of the voltage across all LEDs in the load. This
circuit fault. An external pull-up resistor should be connected to a is compared to the voltage on the LF pin to provide shorted LED
suitable logic supply for simple logic fault flag operation or to the detection. In addition, it is compared against voltage references to
Allegro MicroSystems, Inc.
115 Northeast Cutoff
7
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5秒后页面跳转
TLP250光耦合器：资料手册参数分析
DA14580 低功耗蓝牙系统级芯片(SoC)：资料手册参数分析
INA226 高精度电流和功率监控器：资料手册参数分析
SI2302 N沟道MOSFET：资料手册参数分析
微信公众号
抖音公众号
浙公网安备 33010502006866号 浙ICP备10014259号-119
营业执照ICP证
技术参数
数据手册
如果您发现信息不准确，
