MAX16812 Datasheet, PDF (7/21 Pages) Maxim Integrated Products – Integrated High-Voltage LED Driver with Analog and PWM Dimming Control

Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20, 21
22, 23
24
25
26
27
28
—
Pin Description
NAME
FB
COMP
REFI
REF
CS_OUT
AGND
EN
IN
L_REG
SGND
DD
DGT
CS+
CS-
LV
H_REG
HV
DRV
GT
LX
SRC
SLP
TGRM
DIM
RT
OV
EP
FUNCTION
Low-Side Error Amplifier’s Inverting Input
Low-Side Error Amplifier’s Output. Connect a compensation network from COMP to FB for stable operation.
Reference Input. V_REFI provides the reference voltage for the high-side current-sense amplifier to set the
LED current.
+1.23V Reference Output. Connect an appropriate soft-start capacitor from REF to AGND.
High-Side Current-Sense Amplifier Output. V_{CS_OUT} is proportional to the current through R_CS.
Analog Ground
Enable Input/Undervoltage Lockout. Connect EN to IN through a resistive voltage-divider to program the
UVLO threshold. Connect EN directly to IN to set up the device for 5V internal threshold. Apply a logic-
level input to EN to enable/disable the device.
Positive Power-Supply Input. Bypass with a 1µF ceramic capacitor to AGND.
5V Low-Side Regulator Output. Bypass with a 3.3µF ceramic capacitor to AGND.
Signal Ground
MOSFET’s Drain Voltage-Sense Input. Connect DD to the drain of the external dimming MOSFET.
External Dimming MOSFET’s Gate Drive
High-Side Current-Sense Amplifier’s Positive Input. Connect R_CS between CS+ and CS-. CS+ is
referenced to LV.
High-Side Current-Sense Amplifier’s Negative Input. Connect R_CS between CS- and CS+. CS- is
referenced to LV.
High-Side Reference Voltage Input. A DC voltage at LV sets the lowest reference point for the high-side
current-sense and dimming MOSFET control circuitry.
High-Side Regulator Output. H_REG provides a regulated supply for high-side circuitry. Bypass with a 1µF
ceramic capacitor to LV.
High-Side Positive Supply Voltage Input. HV provides power for dimming and LED current-sense circuitry.
HV is referenced to LV.
Internal MOSFET Gate Driver Output. Connect to a resistor between DRV and GT to set the rise and fall
times at LX.
Internal MOSFET GATE. Connect a resistor between GT and DRV to set the rise and fall times at LX.
Internal MOSFET Drain
Internal Power MOSFET Source
Slope Compensation Setting. Connect an appropriate external capacitor from SLP to AGND to generate a
ramp signal for stable operation.
Dimming Comparator’s Reference/Ramp Generator
Dimming Control Input
Resistor-Programmable Internal Oscillator Setting. Connect a resistor from RT to AGND to set the internal
oscillator frequency.
Overvoltage Protection Input. Connect OV to HI through a resistive voltage-divider to AGND to set the
overvoltage limit for the load. When the voltage at OV exceeds the 1.238V (typ) threshold, the gate drive
(DRV) for the switching MOSFET is disabled. Once V_OV goes below 1.238V by 14mV, the switching
MOSFET turns on again.
Exposed Pad. Connect EP to a large-area ground plane for effective power dissipation. Do not use as the
IC ground connection.
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