HV9911DB4 User Guide

Supertex inc.
HV9911DB4
High Brightness SEPIC LED Driver Demoboard
with High Dimming Ratio and Excellent Current Regulation
General Description
The HV9911DB4 is an LED driver dempboard capable of
driving one to six three-watt LEDs in series from an input of 9.0
- 16VDC. The demoboard uses Supertex’s HV9911 in a SEPIC
topology to drive LED string voltages higher or lower than the
input voltage. The converter has a very good initial regulation
(+/-5%), and excellent line and load regulation over the entire
input and output voltage range (<+/-1%). The full load efficiency
of the converter is typically greater than 85%.
The HV9911DB4 is also protected against open LED and
output short circuit conditions. It is protected against over load
conditions by limiting the input current. It has an excellent PWM
dimming response. The switching frequency of the HV9911DB4
can be synchronized to other HV9911 boards or to an external
350kHz clock by connecting the clock to the SYNC pin of the
HV9911DB4.
Specifications
Parameter
Value
Input voltage (steady state):
Output LED string voltage:
Output current:
9.0 - 16VDC
3V min - 24V max
700mA +/-5%
Output current ripple:
5% typical
Switching frequency:
350kHz
Full load efficiency:
87% (at 13V input)
Open LED protection:
Shuts down at 30V
Output short circuit protection:
Dimensions
Included
56.0mm x 38.2mm
Board Layout and Connection Diagram
VIN
J1
J2
J3
Actual Size: 56.0mm x 38.2mm
Connections:
Input - The input is connected between the terminals of
connector J1 as shown in the connection diagram.
Output - The output is connected between the terminals of
connector J2 as shown.
Enable/PWM Dimming - To enable the board, short pins
PWMD and VDD of connector J3 as shown. To use the PWM
dimming feature of the board, connect an external push-pull
square wave source between terminal PWMD and GND of
connector J3 as shown by the dotted lines.
Doc.# DSDB-HV9911DB4
A032713
SYNC: To synchronize two or more boards, connect the
SYNC pins of all the boards. To synchronize the HV9911DB4
to an external 350kHz clock, connect the clock between
SYNC and GND pins of terminal J3.
Note:
During PWM dimming, VDD of connector J3 should be left
open. Also, the PWM signal must have the proper polarity
with the positive connected to PWMD of J3. Note that
GND of J3 is internally connected to the return path of the
input voltage.
Supertex inc.
www.supertex.com
HV9911DB4
Demoboard Testing:
Fig.1 Efficiency vs. Output Voltage
Normal Operation: Connect the input source and the output
LEDs as shown in the connection diagram and enable the
board. The LEDs will glow with a steady intensity. Connecting
an ammeter in series with the LEDs will allow measurement
of the LED current. The current will be 700mA +/- 5%.
Efficiency (%)
Current Regulation: With the input power to the converter
disconnected, change the input voltage or the LED string
voltage within the specifications mentioned. The current
output of the HV9911DB4 will remain very steady over the
entire line range.
85
80
75
70
65
3
8
13
18
23
Output Voltage (V)
Fig.2 Efficiency vs. Input Voltage
Full Load Efficiency vs. Input Voltage
88
Efficiency (%)
With the supply turned off, change the LED string voltage
within the specified limits and turn the power supply back on.
The current will still be regulated at around 700mA.
Open LED test: Connect a voltmeter across the output
terminals of the HV9911DB4. Start the demoboard normally
and once the LED current reaches a steady state, unplug
one end of the LED string from the demoboard. The output
voltage will rise to about 30V and the HV9911DB4 will shut
down. To restart the converter, disconnect and reconnect the
input voltage (recycle the power to the board).
87
86
85
84
83
82
9
11
15
13
Input Voltage (V)
2. Current Regulation: Fig.3 and Fig.4 show the output
current regulation vs. load voltage and input voltage
respectively. The total current regulation (line and load
combined) is less than 1%.
Short Circuit Test: When the HV9911DB4 is operating in a
steady state, connect a jumper across the terminals of the
LED string. Notice that the output current will immediately
go to zero and the converter will shut down. To restart the
HV9911DB4, recycle the input power to the demoboard.
Output Current (A)
Fig.3 Output Current vs. Output Voltage
PWM Dimming: With the input voltage to the board
disconnected, apply a TTL-compatible, push-pull square
wave signal between PWMD and GND terminals of
connector J3 as shown in the connection diagram. Turn
the input voltage back on and adjust the duty cycle and/or
frequency of the PWM dimming signal. The output current
will track the PWM dimming signal. Note that although the
converter operates perfectly well at 1kHz PWM dimming
frequency, the best PWM dimming ratio can be obtained at
lower frequencies, like 100Hz or 200Hz.
Load Regulation (VIN = 13.5V)
0.710
0.705
0.700
0.695
0.690
3
8
13
18
23
Output Voltage (V)
Output Current (A)
Fig.4 Output Current vs. Input Voltage
Typical Results
1. Efficiency: The efficiency of the converter at various LED
string voltages are shown in Fig.1 (measured at the nominal
input voltage of 24V). Fig.2 shows the full load efficiency
of the converter at varying input voltages. The minimum
efficiency of 68% for the converter occurs at minimum load
voltage.
Doc.# DSDB-HV9911DB4
A032713
Efficiency vs. Load Voltage (VIN = 13.5V)
90
Line Regulation (VO = 24V)
0.710
0.705
0.700
0.695
0.690
9
11
15
13
Input Voltage (V)
2
Supertex inc.
www.supertex.com
HV9911DB4
6. PWM Dimming: Typical PWM dimming response is
shown in Fig.8. Fig.9a shows the rise and Fig.9b shows the
fall of the LED current on an expanded time scale.
3. Normal Operation: The drain voltage of the switching FET
and the output current are shown in Fig.5. It can be seen that
the converter is switching at 350kHz, and the output current
ripple is about 16% (peak to peak).
Fig.8: Typical PWM Dimming Waveforms
Fig.5. Switching waveforms for the HV9911DB4
PWM Dimming Input
Output Current
Drain voltage
LED Current
Fig.9a. Rise Time
(10µs/div)
4. Open LED Protection: Open LED protection for the
circuit is set at 30V. The waveforms in Fig.6 show the output
voltage, drain voltage, and output current during an open
LED condition. The time taken for the over voltage protection
to shut the IC down will depend on the size of the output
capacitor.
PWM Dimming Signal
Fig.6. Open LED Protection
LED Current
Output Voltage
LED Current
Fig.9b. Fall Time
(10µs/div)
Drain Voltage of Q1
PWM Dimming Signal
5. Output Short Circuit Protection: Fig.7 shows the
waveforms for output short circuit condition. The disconnect
FET is turned off in about 300ns. The rise in the output
current will depend on the output voltage and the energy
stored in the output capacitor.
Doc.# DSDB-HV9911DB4
A032713
LED Current
3
Supertex inc.
www.supertex.com
HV9911DB4
7. Input Audio Susceptibility: Fig.10 shows the response
of the converter for a step change in the input voltage from
10 to 16V. The current overshoots by 30% and comes back
into regulation in 7ms.
Fig. 10. Response of the HV9911DB4
to an input voltage change
(Time Scale: 1ms/div)
8. Input Current Ripple: Fig.10 shows the input current
ripple of the converter at full load and 13.5V input. The ripple
current is about 4% (peak to peak).
Input Voltage
LED Current
Silk Screen
Doc.# DSDB-HV9911DB4
A032713
4
Supertex inc.
www.supertex.com
Doc.# DSDB-HV9911DB4
A032713
5
REF
19.1k
R12
REF
C8
open
8.66k
R9
open
R7
6.81k C7
0.1μF
16V
R13
C6
0.1μF
16V
C1
2.2μF
25V
open
R4
J3B
17.4k
R8
Io_SNS
J3A
C2
2.2μF
25V
VDD
J3D
J3C
PWM
CLIM
U1
SC
RT
R11
36k
GND
OVP
FAULT
CS
GATE
VIN
HV9911
COMP
FDBK
IREF
REF
SYNC
C5
1.0μF
16V
1
R5
2
499Ω
261k
R2
33μH
L1
R6
0.1Ω
1W
Q1
FDS3692
C11
1.0μF
50V
C10
1.0μF
50V
C3
1.0μF
50V
2
Io_SNS
L2
100μH
1
C4
2.2μF
50V
D1
SK38-TP
C12
470pF
50V
C9
2.2μF
50V
1k
R14
D2
1N4148
J2B
C13
1.0nF
50V
J2A
R10
0.47Ω
0.5W
Q2
ZXMN6A11G
2
R3
2.43k
R1
56.2k
1
Circuit Schematic:
REF
1
J1A
2
J1B
HV9911DB4
Supertex inc.
www.supertex.com
HV9911DB4
Bill of Materials
Manufacturer
Manufacturer’s Part
Number
TDK Corp
C3225X7R1E225K
Kemet
C1210C105K5RACTU
2.2μF, 50V X7R ceramic chip capacitor SMD1210
TDK Corp
C3225X7R1H225K
C5
1.0μF, 16V X7R ceramic chip capacitor SMD0805
TDK Corp
C2012X7R1C105K
C6, C7
0.1μF, 16V X7R ceramic chip capacitor SMD0805
Murata
GRM219R71C104KA01D
-
-
-
SMD0805
Kemet
C0805C471K5RACTU
C13
1.0nF, 50V X7R ceramic chip capacitor SMD0805
Kemet
C0805C102K5RACTU
1
D1
80V, 3A schottky diode
SMC
Micro
Commercial
SK38-TP
10
2
J1, J2
Side Entry 2-pin male header
Thru-Hole
JST Sales
S2B-EH
11
1
J3
Side Entry 4-pin male header
Thru-Hole
JST Sales
S4B-EH
12
1
L1
33μH, 3A rms, 6A SAT inductor
SMT
13
1
L2
100μH, 0.86A rms, 1.0A SAT inductor
SMT
14
1
Q1
100V, 4.55A N-Channel MOSFET
SO-8
Fairchild
FDS3692
15
1
Q2
60V, 2.7A N-Channel MOSFET
SOT-89
Zetex, Inc.
ZXMN6A11G
16
1
R1
56.2kΩ, 1%, 1/4W chip resistor
SMD1206
-
-
17
1
R2
261kΩ, 1%, 1/8W chip resistor
SMD0805
-
-
18
1
R3
2.43kΩ, 1%, 1/8W chip resistor
SMD0805
-
-
19
1
R5
499Ω, 1%, 1/8W chip resistor
SMD0805
-
-
20
1
R6
0.1Ω, 5%, 1W chip resistor
SMD2512
-
--
21
1
R8
17.4kΩ, 1%, 1/8W chip resistor
SMD0805
-
-
22
1
R9
8.66kΩ, 1%, 1/8W chip resistor
SMD0805
-
-
23
1
R10
0.47Ω, 1%, 1/2W chip resistor
SMD2010
-
-
24
1
R11
36kΩ, 1%, 1/8W chip resistor
SMD0805
-
-
25
1
R12
19.1kΩ, 1%, 1/8W chip resistor
SMD0805
-
-
26
1
R13
6.81kΩ, 1%, 1/8W chip resistor
SMD0805
-
-
27
1
R14
1.0kΩ, 1%, 1/4W chip resistor
SMD1206
-
-
28
1
U1
Switchmode LED Driver
SO-16
Supertex
HV9911NG-G
Item
Qty
Ref Des Description
1
2
2
3
3
2
C4, C9
4
1
5
1
6
3
7
1
C12
470pF, 50V, X7R ceramic chip
capacitor
8
1
9
C1, C2
Package
2.2μF, 25V X7R ceramic chip capacitor SMD1210
C3, C10,
1.0μF, 50V X7R ceramic chip capacitor SMD1210
C11
R4, R7, C8 open
Cooper
Electronics
Cooper
Electronics
DR127-330
DR74-101
Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives
an adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liability
to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry and
specifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com)
Supertex inc.
©2013 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited.
Doc.# DSDB-HV9911DB4
A032713
6
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com