HV9980 Datasheet, PDF (1/10 Pages) Supertex, Inc – 3-Channel LED Array Driver IC

HV9980
3-Channel LED Array Driver IC
Features
► Integrated 200V, 25Ω (typ.) MOSFETs
► Programmable output current to 80mA per channel
► TTL compatible PWM dimming inputs
► 3-Phase synchronous operation
► Leading edge blanking
► Short circuit protection with skip mode
► Over-temperature protection
Applications
► LCD panel backlighting
► DLP RPTV or projector LED engine driver
► RGB decorative lighting
► General LED lighting
General Description
The HV9980 is a fully integrated 3-channel peak-current
PWM controller for driving buck converters in constant output
current mode. It is optimized for use with a large array of
20~80mA LED strings, where multiple HV9980 ICs are used
sharing a common clock and a common reference voltage.
Both the clock and the voltage reference are external to the
HV9980 for improved output current accuracy and uniform
illumination. The output currents are programmed by
controlling peak source current in each of the three internal
200V, 25Ω switching MOSFETs.
The peak current is detected by monitoring voltage at external
sense resistors connected to RSENSE1-3. The switching
MOSFET is turned off when the corresponding current sense
signal exceeds the reference voltage applied at REF1-3 (in
the case of normal output signal polarity). Beginning of the
next switching cycle is determined by the external clock
signal received at the CLK input. All three channels operate
at a switching frequency of 1/6 of the external clock frequency
and positioned 120º out-of-phase for the purpose of input and
output ripple current reduction. Each channel is protected
from an output short circuit condition. When an over-current
condition is detected in the output switch (RSENSE1-3),
the corresponding channel shuts down for 200us. HV9980
recovers automatically, when the short circuit condition is
removed. Each current sense input (CS1-CS3) is equipped
with a leading edge blanking delay to prevent false triggering
of the current sense comparators due to circuit parasitics.
Over-temperature protection is included to prevent
destructive failures due to over-heating. Programmable
slope compensation is available at each CS input. AGND and
PGND1-3 must be tied together on the printed circuit board.
VDD1-3 must be also connected together on the PCB.
Typical Application Circuit
+V_IN
C_IN
C1
C2
C3
D1
D2
D3
L1
L2
L3
PWMD1
4
PWMD2
9
PWMD3
12
CLOCK
3
POL
6
5
AGND
+8V
21
2
23
22
24
C_DD1
1
R_SENSE1
1
17
U1
HV9980WG
8
19
18
20
C_DD2
2
R_SENSE2
2
16
11
14
15
13
C_DD3
3
R_SENSE3
3
R_REF1
1
REF1
C_REF1
1
R_REF2
7
REF2
C_REF2
2
R_REF3
10
REF3
C_REF3
3