SUTEX HV9861ANG-G Led driver with average-mode, constant current control Datasheet

Supertex inc.
HV9861A
LED Driver with Average-Mode,
Constant Current Control
Features
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General Description
Fast average current control
Programmable constant off-time switching
PWM / linear dimming input
Output short circuit protection with skip mode
Ambient operating temperature -40OC to +125OC
Pin-compatible with the HV9910B and HV9961
The IC is equipped with a current limit comparator for hiccup-mode
output short circuit protection. Internal over-temperature protection
is provided. The internally regulated voltage (VDD) for the HV9861A
is 7.5V.
Applications
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The HV9861A is a patented, average-mode, constant current control
LED driver IC operating in a constant off-time mode. Unlike the
HV9910B, this control IC does not produce a peak-to-average error,
and therefore greatly improves the accuracy, line and load regulation
of the LED current without any need for loop compensation or highside current sensing. The output LED current accuracy is ±3%.
DC/DC or AC/DC LED driver applications
LED backlight driver for LCD displays
General purpose constant current source
LED signage and displays
Architectural and decorative LED lighting
LED street lighting
The IC can be powered from a 12 - 450V supply. A PWM dimming
input is provided that accepts an external control TTL-compatible
signal. The output current can be programmed by an internal 270mV
reference, or controlled externally through a 0 - 1.5V dimming input.
The IC is pin-to-pin compatible with the Supertex HV9910B and
HV9961, and can be used as a drop-in replacement for many
applications to improve the LED current accuracy and regulation.
Typical Application Circuit
12 to
450VDC
LED
Load
1
VIN
5 PWMD
GATE 4
HV9861A
6 VDD
CS 2
7 LD
RT 8
GND
3
Supertex inc.
RT
RCS
Sets
LED
Current
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
HV9861A
Pin Description
Ordering Information
Package Options
8-Lead SOIC
Device
16 NC
NC 2
15 NC
NC 3
14 RT
CS 4
13 LD
16-Lead SOIC
4.90x3.90mm body
1.75mm height (max)
1.27mm pitch
9.90x3.90mm body
1.75mm height (max)
1.27mm pitch
HV9861ALG-G
HV9861ANG-G
HV9861A
VIN 1
-G indicates package is RoHS compliant (‘Green’)
VIN 1
8 RT
CS 2
7 LD
GND 5
6 VDD
GND 3
5 PWMD
GATE 4
12 VDD
NC 6
11 NC
NC 7
10 NC
GATE 8
8-Lead SOIC (LG)
(top view)
9
16-Lead SOIC (NG)
(top view)
Product Marking
Absolute Maximum Ratings
Parameter
Value
VIN to GND
-0.5V to +470V
VDD to GND
12V
CS, LD, PWMD, GATE, RT to GND
Y = Last Digit of Year Sealed
WW = Week Sealed
L = Lot Number
= “Green” Packaging
YWW
9861A
LLLL
Package may or may not include the following marks: Si or
8-Lead SOIC (LG)
-0.3V to (VDD +0.3V)
Junction temperature range
-40°C to +150°C
Storage temperature range
-65°C to +150°C
Top Marking
HV9861ANG
YWW
LLLLLLLL
Bottom Marking
Continuous power dissipation (TA = +25°C)
8-Lead SOIC
16-Lead SOIC
650mW
1000mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
CCCCCCCCC AAA
Y = Last Digit of Year Sealed
WW = Week Sealed
L = Lot Number
C = Country of Origin*
A = Assembler ID*
= “Green” Packaging
*May be part of top marking
Package may or may not include the following marks: Si or
16-Lead SOIC (NG)
Thermal Resistance
Package
θJA
8-Lead SOIC
128OC/W
16-Lead SOIC
82OC/W
Electrical Characteristics (Specifications are at T
A
Sym
Description
= 25°C. VIN = 12V, VLD = VDD, PWMD = VDD unless otherwise noted))
Min
Typ
Max
Unit
Conditions
Input
VINDC
Input DC supply voltage range1
*
12
-
450
V
IINSD
Shut-down mode supply current
*
-
0.5
1
mA
DC input voltage
Pin PWMD to GND
Notes:
1. Also limited by package power dissipation limit, whichever is lower.
*
Denotes the specifications which apply over the full operating ambient temperature range of -40°C < TA < +125°C.
Supertex inc.
PWMD
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2
HV9861A
Electrical Characteristics (Specifications are at T
A
Sym
Description
= 25°C. VIN = 12V, VLD = VDD, PWMD = VDD unless otherwise noted))
Min
Typ
Max
Unit
Conditions
Internal Regulator
VDD
Internally regulated voltage
-
7.25
7.50
7.75
V
ΔVDD, line
Line regulation of VDD
-
-
-
1
V
ΔVDD, load
Load regulation of VDD
-
-
-
100
mV
*
6.45
-
-
V
VIN rising
-
-
500
-
mV
VIN falling
VDD voltage margin
*
500
-
-
mV
∆VDD(UV) = VDD - UVLO
Maximum input current
(limited by UVLO)
#
3.5
-
-
#
1.5
-
-
VDD undervoltage lockout
threshold
VDD undervoltage lockout
hysteresis
UVLO
∆UVLO
∆VDD(UV)
IIN,MAX
mA
500pF at GATE; RT = 226kΩ
VIN = 12 - 450V,
500pF at GATE; RT = 226kΩ
IDD(ext) = 0 - 1mA,
500pF at GATE; RT = 226kΩ
VIN = 12V, TA = 25OC
VIN = 12V, TA = 125OC
PWM Dimming
VEN(lo)
PWMD input low voltage
*
-
-
0.8
V
VIN = 12 - 450V
VEN(hi)
PWMD input high voltage
*
2.2
-
-
V
VIN = 12 - 450V
Internal pull-down current at
PWMD
-
8.5
-
13.5
μA
VPWMD = 0.8V
Current sense reference voltage
-
262
-
280
mV
---
AV(LD)
LD-to-CS voltage ratio
-
0.175
-
0.182
-
---
AV • VLD(OFFSET)
LD-to-CS voltage offset
-
-10
-
10
mV
Offset = VCS - (AV(LD) • VLD);
VLD = 1.2V
CS threshold temp regulation
#
-
-
5
mV
---
LD input voltage, shutdown
-
-
150
-
mV
VLD falling
LD input voltage, enable
-
-
200
-
mV
VLD rising
TBLANK
Current sense blanking interval
*
140
-
290
ns
---
TON(min)
Minimum on-time
-
-
-
760
ns
CS = VCS + 30mV
Maximum steady-state duty
cycle
*
80
-
-
%
Reduction in output LED current
may occur beyond this duty cycle
Hiccup threshold voltage
*
410
-
500
mV
---
TDELAY
Current limit delay CS-to-GATE
-
-
-
150
ns
CS = VCS + 30mV
THICCUP
Short circuit hiccup time
-
500
-
850
μs
---
TON(min)
Minimum on-time (short circuit)
-
-
-
430
ns
CS = VDD
IEN
Average Current Sense Logic
VCS
ΔVCS(TEMP)
VLD(OFF)
ΔVLD(OFF)
DMAX
Short Circuit Protection
VCS
Notes:
*
Denotes the specifications which apply over the full operating ambient temperature range of -40°C < TA < +125°C.
# Guaranteed by design.
Supertex inc.
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
3
HV9861A
Electrical Characteristics (Specifications are at T
A
Sym
Description
= 25°C. VIN = 12V, VLD = VDD, PWMD = VDD unless otherwise noted))
Min
Typ
Max
Unit
Conditions
-
32
40
48
-
8
10
12
Sourcing current
-
0.165
-
-
A
VGATE = 0V, VDD = 7.5V
ISINK
Sinking current
-
0.165
-
-
A
VGATE = VDD, VDD = 7.5V
tRISE
Output rise time
-
-
30
50
ns
CGATE = 500pF, VDD = 7.5V
tFALL
Output fall time
-
-
30
50
ns
CGATE = 500pF, VDD = 7.5V
Shut-down temperature
#
128
140
-
O
Hysteresis
#
-
20
-
O
TOFF Timer
TOFF
Off-time
μs
RT = 1MΩ
RT = 226kΩ
GATE Driver
ISOURCE
Over-temperature Protection
TSD
ΔTSD
C
---
C
---
Notes:
# Guaranteed by design.
Functional Block Diagram
VIN
Regulator
VDD
+
-
UVLO
POR
0.15/0.20V
LD
+
-
MIN (VLD • 0.18, 0.27V)
GATE
Auto-REF
CS
Latch
Enable
Blanking
IN
Average Current
Control Logic
OUT
PWMD
GND
0.45V
+
-
11µA
R Q
S Q
CLK
HV9861A
Supertex inc.
650µs
TOFF
Timer
i
Current
Mirror
RT
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4
HV9861A
General Description
Peak-current control (as in the HV9910B) of a buck converter is the most economical and simple way to regulate
its output current. However, it suffers accuracy and regulation problems that arise from the so-called peak-to-average
current error, contributed to by the current ripple in the output inductor and the propagation delay in the current sense
comparator. The full inductor current signal is unavailable
for direct sensing at the ground potential in a buck converter
when the control switch is referenced to the same ground
potential because the control switch is only conducting for
small periods. While it is very simple to detect the peak current in the switch, controlling the average inductor current
is usually implemented by level translating the sense signal from +VIN. Though this is practical for relatively low input
voltage VIN, this type of average-current control may become
excessively complex and expensive in offline AC or other
high-voltage DC applications.
The HV9861A employs Supertex’ patented control scheme,
achieving fast and very accurate control of average current
in the buck inductor through sensing the switch current only.
No compensation of the current control loop is required. The
LED current response to PWMD input is similar to that of the
HV9910B. The inductor current ripple amplitude does not affect this control scheme significantly, and therefore, the LED
current is independent of the variation in inductance, switching frequency or output voltage. Constant off-time control of
the buck converter is used for stability and to improve the
LED current regulation over a wide range of input voltages.
(Note that, unlike the HV9910B, this IC does not support the
constant-frequency mode of operation.)
OFF Timer
The timing resistor connected to RT determines the off-time
of the gate driver, and it must be wired to GND. (Wiring this
resistor to GATE as with the HV9910B is no longer supported.) The equation governing the off-time of the GATE output
is given by:
TOFF (µs) =
RT (kΩ)
25
(1)
+ 0.3
Within the range of 30kΩ ≤ RT ≤ 1.0MΩ.
Average Current Control Feedback and Output
Short Circuit Protection
The current through the switching MOSFET source is averaged and used to give constant-current feedback. This current is detected using a sense resistor at the CS pin. The
Supertex inc.
feedback operates in a fast open-loop mode. No compensation is required. Output current is programmed simply as:
ILED =
0.27V
RCS
(2)
When the voltage at the LD input VLD ≥ 1.5V. Otherwise:
I
=
LED
VLD • 0.18
RCS
(3)
The above equations are only valid for continuous conduction of the output inductor. It is a good practice to design the
inductor such that the switching ripple current in it is 30~40%
of its average peak-to-peak, full load, DC current. Hence,
the recommended inductance can be calculated as:
LO =
VO(MAX) • TOFF
0.4 • IO
(4)
The duty-cycle range of the current control feedback is limited to D ≤ 0.8. A reduction in the LED current may occur
when the LED string voltage VO is greater than 80% of the
input voltage VIN of the HV9861A LED driver.
Reducing the output LED voltage VO below VO(MIN) = VIN •
DMIN, where DMIN = 760ns/(TOFF +760ns), may also result
in the loss of regulation of the LED current. This condition,
however, causes an increase in the LED current and can
potentially trip the short-circuit protection comparator.
The typical output characteristic of the HV9861A LED driver
is shown in Fig.1. The corresponding HV9910B characteristic is given for comparison.
Output Characteristics
0.60
0.55
LED Current (A)
Application Information
VIN = 170VDC
0.50
0.45
0.40
HV9861A
0.35
0.30
0.25
HV9910B
0
10
20
30
40
50
60
Output Voltage (V)
Fig.1. Typical output characteristic of an HV9861A LED
driver.
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5
HV9861A
The short circuit protection comparator trips when the voltage at CS exceeds 0.45V. When this occurs, the GATE offtime THICCUP = 650µs is generated to prevent stair-casing
of the inductor current and potentially its saturation due to
insufficient output voltage. The typical short-circuit current is
shown in the waveform of Fig. 2.
0.45V/RCS
650µs
Fig.2. Short-circuit inductor current.
A leading-edge blanking delay is provided at CS to prevent
false triggering of the current feedback and the short circuit
protection.
Linear Dimming
When the voltage at LD falls below 1.5V, the internal 270mV
reference to the constant-current feedback becomes overridden by VLD • 0.18. As long as the current in the inductor
remains continuous, the LED current is given by the equation (3) above. However, when VLD falls below 150mV, the
GATE output becomes disabled. The GATE signal recovers,
when VLD exceeds 200mV. This is required in some applications to be able to shut the LED lamp off with the same signal
input that controls the brightness. The typical linear dimming
response is shown in Fig.3.
LD Response Characteristics
0.40
0.35
LED Current (A)
0.30
pulse-width modulated signal of a measured amplitude below 1.5V should be applied at LD.
Input Voltage Regulator
The HV9861A can be powered directly from a 12 ~ 450VDC
supply through its VIN input. When this voltage is applied at
the VIN pin, the HV9861A maintains a constant 7.5V level
at VDD. This voltage can be used to power the IC and external circuitry connected to VDD within the rated maximum
current or within the thermal ratings of the package, whichever limit is lower. The VDD pin must be bypassed by a low
ESR capacitor to provide a low impedance path for the high
frequency current of the GATE output. The HV9861A can
also be powered through the VDD pin directly with a voltage
greater than the internally regulated 7.5V, but less than 12V.
Despite the instantaneous voltage rating of 450V, continuous voltage at VIN is limited by the power dissipation in the
package. For example, when these ICs draw IIN = 2.0mA
from the VIN input, and the 8-lead SOIC package is used,
the maximum continuous voltage at VIN is limited to:
VIN(MAX) =
TJ(MAX) - TA
Rθ,J-A • IIN
= 390V
(5)
Where the ambient temperature TA = 25OC, the maximum
working junction temperature TJ(MAX) = 125OC, the junctionto-ambient thermal resistance Rθ,JA = 128OC/W.
In such cases, when it is needed to operate the HV9861A
from a higher voltage, a resistor or a Zener diode can be
added in series with the VIN input to divert some of the power loss from the IC. In the above example, using a 100V
Zener diode will allow the circuit to work up to 490V. The
input current drawn from the VIN pin is represented by the
following equation:
0.25
IIN ≈ 1.0mA + QG • fS
0.20
0.15
In the above equation, fS is the switching frequency, and QG
is the GATE charge of the external FET obtained from the
manufacturer’s datasheet.
0.10
0.05
0
(6)
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
LD (V)
Fig.3. Typical linear dimming response of an HV9861A
LED driver
The linear dimming input could also be used for “mixedmode” dimming to expand the dimming ratio. In such case a
Supertex inc.
GATE Output
The GATE output of the HV9861A is used to drive an external MOSFET. It is recommended that the gate charge QG
of the external MOSFET be less than 25nC for switching
frequencies ≤100kHz and less than 15nC for switching frequencies >100kHz.
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6
HV9861A
PWM Dimming
Due to the fast open-loop response of the average-mode current control loop of the HV9861A, the PWM dimming performance nearly matches that of the HV9910B. The inductor current waveform comparison is shown in Fig. 4.
The rising and falling edges are limited by the current slew
rate in the inductor. The first switching cycle is terminated
upon reaching the 270mV (VLD • 0.18) level at CS. The circuit is further reaching its steady-state within 3~4 switching
cycles regardless of the switching frequency.
Fig.4. Typical PWM dimming response of an HV9861A
LED driver.
[CH2 (red): PWMD; CH4 (green): Inductor Current; CH3 (blue):
Same as HV9910B for comparison]
Pin Description
Pin #
Function
Description
8-Lead SOIC
16-Lead SOIC
1
1
VIN
This pin is the input of an 12 - 450V linear regulator.
2
4
CS
This pin is the current sense pin used to sense the FET current by means
of an external sense resistor.
3
5
GND
Ground return for all internal circuitry. This pin must be electrically connected to the ground of the power train.
4
8
GATE
This pin is the output GATE driver for an external N-channel power
MOSFET.
5
9
PWMD
This is the PWM dimming input of the IC. When this pin is pulled to GND,
the gate driver is turned off. When the pin is pulled high, the gate driver
operates normally.
6
12
VDD
This is the power supply pin for all internal circuits. It must be bypassed
with a low ESR capacitor to GND (at least 0.1μF).
7
13
LD
This pin is the linear dimming input, and it sets the current sense threshold as long as the voltage at this pin is less than 1.5V. If voltage at LD falls
below 150mV, the GATE output is disabled. The GATE signal recovers at
200mV at LD.
8
14
RT
A resistor connected between this pin and GND programs the GATE offtime.
-
2, 3, 6, 7, 10,
11, 15, 16
NC
No connection.
Supertex inc.
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
7
HV9861A
8-Lead SOIC (Narrow Body) Package Outline (LG)
4.90x3.90mm body, 1.75mm height (max), 1.27mm pitch
D
θ1
8
E
E1
L2
Note 1
(Index Area
D/2 x E1/2)
L
1
θ
L1
Top View
Gauge
Plane
Seating
Plane
View B
A
View B
Note 1
h
h
A A2
Seating
Plane
b
e
A1
A
Side View
View A-A
Note:
1. This chamfer feature is optional. A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier can be: a molded mark/identifier;
an embedded metal marker; or a printed indicator.
Symbol
Dimension
(mm)
A
A1
A2
b
MIN
1.35*
0.10
1.25
0.31
NOM
-
-
-
-
MAX
1.75
0.25
1.65*
0.51
D
E
E1
4.80* 5.80* 3.80*
4.90
6.00
3.90
5.00* 6.20* 4.00*
e
1.27
BSC
h
L
0.25
0.40
-
-
0.50
1.27
L1
1.04
REF
L2
0.25
BSC
JEDEC Registration MS-012, Variation AA, Issue E, Sept. 2005.
* This dimension is not specified in the JEDEC drawing.
Drawings are not to scale.
Supertex Doc. #: DSPD-8SOLGTG, Version I041309.
Supertex inc.
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
8
θ
θ1
0O
5O
-
-
8O
15O
HV9861A
16-Lead SOIC (Narrow Body) Package Outline (NG)
9.90x3.90mm body, 1.75mm height (max), 1.27mm pitch
D
16
θ1
E1 E
Note 1
(Index Area
D/2 x E1/2)
L2
1
L
Top View
View B
A
A A2
e
A1
View
B
h
h
Seating
Plane
Seating
Plane
θ
L1
Gauge
Plane
Note 1
b
Side View
View A-A
A
Note:
1. This chamfer feature is optional. If it is not present, then a Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier can be:
a molded mark/identifier; an embedded metal marker; or a printed indicator.
Symbol
Dimension
(mm)
A
A1
A2
b
D
E
E1
MIN
1.35*
0.10
1.25
0.31
9.80*
5.80* 3.80*
NOM
-
-
-
-
9.90
6.00
MAX
1.75
0.25
1.65*
0.51
3.90
10.00* 6.20* 4.00*
e
1.27
BSC
h
L
0.25
0.40
-
-
0.50
1.27
L1
L2
1.04 0.25
REF BSC
θ
θ1
0O
5O
-
-
8O
15O
JEDEC Registration MS-012, Variation AC, Issue E, Sept. 2005.
* This dimension is not specified in the JEDEC drawing.
Drawings are not to scale.
Supertex Doc. #: DSPD-16SONG, Version G041309.
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline
information go to http://www.supertex.com/packaging.html.)
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.
©2012 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited.
Doc.# DSFP-HV9861A
A010312
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
9
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