HV9911DB1 User Guide

Supertex inc.
HV9911DB1
High Brightness Boost LED Driver Demoboard
with 1:3000 Dimming Ratio and Excellent Current Regulation
General Description
The HV9911DB1 is an LED driver capable of driving up to 20
one-watt LEDs in series from an input of 21 - 27VDC. The
demoboard uses Supertex’s HV9911 in a boost topology.
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 90%.
The HV9911DB1 is also protected against open LED and
output short circuit conditions. It is also protected under
input undervoltage conditions by limiting the input current.
It has an excellent PWM dimming response, with typical rise
and fall times less than 2.0μs, which will allow high PWM
dimming ratios.
The switching frequency of the HV9911DB1 can be
synchronized to other HV9911 boards or to an external
200kHz clock by connecting the clock to the SYNC pin of the
HV9911DB1.
The HV9911DB1 includes and RC filter to prevent false
triggering of the short circuit protection during PWM dimming,
which was noticed with the HV9911DB1. This improvement
makes the HV9911DB1 immune to turn-on current spikes
in most cases. For a detailed explanation of the origin of
the turn-on spike and the effect of the RC filter on the short
circuit response time, please refer to the HV9911 datasheet.
Specifications
Parameter
Value
Input voltage (steady state):
Output LED string voltage:
Output current:
21V – 27VDC
35V min - 80V max
350mA +/-5%
Output current ripple:
10% typical
Switching frequency:
200kHz
Full Load efficiency:
93% (at 24V input)
Open LED protection:
Shuts down at 92V
Output short circuit protection:
Included
Input under voltage protection:
Included
1:3000 dimming ratio
at 200Hz
PWM dimming:
Board Layout and Connection Diagram
+
-
VIN
+
4
3
2
1
Actual size: 64mm x 34.5mm
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 just enable the board, short pins
PWMD and VDD of connector J3 as shown by the dashed
lines. To PWM dim the board, connect the external pushpull waveform source between terminals PWMD and GND
of connector J3 as shown by the solid lines.
Doc.# DSDB-HV9911DB1
A032713
SYNC - To synchronize two or more boards, connect the
SYNC pins of all the boards together. To synchronize the
HV9911DB1 to an external 200kHz clock, connect the clock
between the SYNC and GND pins of terminal J3.
Note:
During PWM dimming, pin 2 of connector J3 should be left
open. Also, the PWM signal must have the proper polarity
with the positive connected to pin 3 of J3. Note that pin 4
of J3 is internally connected to the return path of the input
voltage.
Supertex inc.
www.supertex.com
HV9911DB1
Testing The Demoboard:
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 350mA +/- 5%.
Efficiency (%)
95
Current Regulation: With the input power to the converter
disconnected, change the LED string voltage within
the specifications mentioned. The current output of the
HV9911DB1 will remain very steady over the entire load
range. Vary the input voltage while the circuit is operational.
The current will be regulated over the entire line range.
94
93
92
91
90
35
40
45
50
55
60
65
70
75
80
Output Voltage (V)
Fig. 1. Efficiency vs. Output Voltage
Efficiency (%)
95
Open LED test: Connect a voltmeter across the output
terminals of the HV9911DB1. Start the demoboard normally
and once the LED current reaches steady state, unplug
one end of the LED string from the demoboard. The output
voltage will rise to about 92V and then the HV9911DB1
will shut down. To restart the converter, disconnect and
reconnect the input voltage (recycle the power to the board).
94
93
92
91
90
20
22
24
26
28
Input Voltage (V)
Fig. 2. Efficiency vs. Input Voltage
Output Current (A)
Short Circuit Test: When the HV9911DB1 is operating in
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
HV9911DB1, recycle the input power to the demoboard.
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 1.0kHz PWM dimming frequency, the widest
PWM dimming ratio can be obtained at lower frequencies
like 100 or 200Hz.
0.354
0.352
0.35
0.348
0.346
35
40
45
50
55
60
65
70
75
80
Output Voltage (V)
Output Current (A)
Fig. 3. Output Current vs. Output 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 93% for the converter occurs at 21V input and full
load output.
0.354
0.352
0.350
0.348
0.346
20
22
24
26
28
Input Voltage (V)
Fig. 4. Output Current vs. Input Voltage
2. Current Regulation: Figs. 3 and 4 show the output current regulation vs. output voltage and input voltage respectively. The total current regulation (line and load combined)
is found to be less than 1%.
Doc.# DSDB-HV9911DB1
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Supertex inc.
www.supertex.com
HV9911DB1
5. Output Short Circuit Protection: Fig. 7 shows the
waveforms for output short circuit condition. The disconnect
FET is turned off in less than 300ns. The rise in the output
current will depend on the input voltage and the value of
inductor L1. The same protection will also help in protecting
the LEDs in case the output voltage increases beyond the
LED string voltage.
0.4
1.6
0.3
1.4
0.2
1.2
0.1
25
20
15
10
Input Current (A)
Output Current (A)
3. Input Under Voltage Protection: Input under voltage
protection is provided by limiting the input current at low input voltages. Fig. 5 shows the output and input currents at
voltages less than the minimum rated voltage. The LED current will decrease as the input voltage falls and the input
current limits to about 1.4A. Note that the input current limit
is not a hard limit as the slope compensation added to the
peak current sense signal will allow a small change in the
input current with a decrease in the input voltage.
Output Voltage
Output Current
1.0
Input Voltage (V), Sweep
Input Current
Output Current
Fig. 5. Input Under Voltage Behavior
Fig. 7:Output Short Circuit Protection
(500ns/div)
4. Open LED Protection: Open LED protection for the circuit is set at 92V. 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.
Output Voltage
LED Current
Drain Voltage of Q1
Fig. 6: Open LED Protection
(20μs/div)
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Supertex inc.
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HV9911DB1
6. PWM Dimming: The rise and fall transitions of the LED
current during PWM dimming are shown in Figs. 8 and 9, at
output voltages of 80 and 40V respectively. The timescale
for all waveforms is set at 5.0μs/div. The rise and fall times
are less than 1.0μs in each case. Thus, a PWM dimming
ratio of 1:3000 is achievable at a PWM dimming frequency
of 200Hz.
PWM dimming input
PWM dimming input
Output Voltage
Output Voltage
LED Current
LED Current
Fig. 8a: Rise time of LED Current at
80V output (5μs/div)
Fig. 8b: Fall time of LED Current at
80V output (5μs/div)
PWM dimming input
PWM dimming input
Output Voltage
Output Voltage
LED Current
LED Current
Fig. 9a: Rise time of LED Current at
40V output (5μs/div)
Fig. 9b: Fall time of LED Current at
40V output (5μs/div)
Silk Screen:
Doc.# DSDB-HV9911DB1
A032713
4
Supertex inc.
www.supertex.com
Doc.# DSDB-HV9911DB1
A032713
REF
REF
J1A
J1B
J4
1
2
5
J5
R13
REF
J6
C8
6.8nF
C7
2.2nF
8.66kΩ
C6
0.1μF
16V
J3A
7.87kΩ
R9
C1
2.2μF
25V
J7
17.4kΩ
R8
20kΩ
R7
IO_SNS
16.2kΩ
R12
C1
2.2μF
25V
OPEN
R4
J3B
J3D
J3C
9
14
16
15
10
8
CLIM
1
VDD VIN
2
13
6
R11
49.9kΩ
4
PWM SC GND
OVP
FAULT
CS
2
453kΩ
R2
1.0kΩ
R5
IO_SNS
R6
0.15Ω
1/2W
Q2
FDS 3692
D1
B1100-13
C4
1.0μF
100V
C9
1.0μF
100V
C10
470pF
Specifications:
Input: 21 - 27VDC
Output Voltage: 40 - 80V
Output Current: 350mA
Overvoltage: 92V
Short Circuit Protection Included
12
11
5
3
RT 7
GATE
HV9911
COMP
FDBK
IREF
REF
SYNC
C5
1.0μF
16V
L1
220μH
(CDRH127/LDNP-221MC)
1
1kΩ
R14
R3
1.13kΩ
2
J2B
C11
10nF
J2A
R10
1.24Ω
1/4W
Q1
TN251DN8
R1
82.5kΩ
1
HV9911DB1
Circuit Schematic:
Supertex inc.
www.supertex.com
HV9911DB1
Bill of Materials
Item Quan Ref Des Description
Package
Manufacturer
Manufacturer’s Part
Number
SMD1210
TDK Corp
C3225X7R1H225K
Radial
EPCOS Inc
B32522C1105J
1
2
C1, C2 2.2µF, 25V, X7R ceramic chip capacitor
2
2
C4, C9 1µF, 100V metal polyester capacitor
3
1
C5
1µF, 16V X7R ceramic chip capacitor
SMD0805
TDK Corp
C2012X7R1C105K
4
1
C6
0.1µF, 16V X7R ceramic chip capacitor
SMD0805
Murata
GRM219R71C104KA01D
5
1
C7
SMD0805
TDK Corp
C2012C0G1H222J
6
1
C8
SMD0805
TDK Corp
C2012C0G1H682J
7
1
C10
470pF, 50V X7R ceramic chip capacitor
SMD0805
AVX Corp
08055C471KAT2A
8
1
C11
10nF, 50V X7R ceramic chip capacitor
SMD0805
TDK Corp
C2012X7R1H103K
9
1
D1
100V, 1A schottky diode
SMA
Diodes Inc.
B1100-13
10
2
Thru-Hole
JST Sales
S2B-EH
11
1
J3
Side Entry 4-pin male header
Thru-Hole
JST Sales
S4B-EH
12
1
L1
220µH, 2.0A sat, 1.5A rms inductor
SMT
Sumida
CDRH127/LDNP-221MC
13
1
Q1
100V, 4.55A N-Channel MOSFET
SO-8
Fairchild
FDS3692
14
1
Q2
100V, 1.5ohm N-Channel MOSFET
SOT-89
Supertex
TN2510N8
15
1
R1
82.5kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-0782K5L
16
1
R2
453kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-07453KL
17
1
R3
1.13kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-071K13L
18
1
R4
open
-
-
-
19
2
SMD0805
Yageo
RC0805FR-071KL
20
1
R6
0.15Ω, 1%, 1/2W chip resistor
SMD2010
Vishay/ Dale
WSL2010R1500FEA
21
1
R7
20kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-0720KL
22
1
R8
17.4kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-0717K4L
23
1
R9
7.87kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-077K87L
24
1
R10
1.24Ω, 1%, 1/4W chip resistor
SMD1206
Yageo
RC1206FR-071R24L
25
1
R11
49.9kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-0749K9L
26
1
R12
16.2kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-0716K2L
27
1
R13
8.66kΩ, 1%, 1/8W chip resistor
SMD0805
Yageo
RC0805FR-078K66L
28
1
U1
Switchmode LED Driver
with High Current Accuracy
SO-16
Supertex
HV9911NG-G
2.2nF, 5%, 50V C0G ceramic chip
capacitor
6.8nF, 5%, 50V C0G ceramic chip
capacitor
J1, J2 Side Entry 2-pin male header
R5, R14 1.0kΩ, 1%, 1/8W chip resistor
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-HV9911DB1
A032713
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1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com