Supertex inc.
Switch Dimmable
LED Driver
Features
General Description
HV9801A
►
Four level switch dimming
►
Very accurate current regulator
►
Output over-current / short circuit protection
►
IC over-temperature protection
►
Available in 8L-SOIC and 16L-SOIC packages
The HV9801A LED driver is ideally suited for switch dimmable
applications using LED bulbs and fixtures.
Through switch dimming, the lamp can be adjusted to four
discrete brightness levels by rapid cycling of the light switch.
The brightness levels are traversed in up and down manner.
Brightness resumes at the highest level when power is
removed for more than a second.
The device can be powered directly from rectified AC through
an internal VDD regulator rated at 450V.
►
Switch dimmable LED bulbs and fixtures
Applications
Typical Application Circuit
VIN
BUS
AC
L
VIN
GATE
HV9801A
CS
GND
VDD
RT
CDD
RT
RCS
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
HV9801A
Ordering Information
Package Options
Device
4.90x3.90mm body
1.75mm height (max)
1.27mm pitch
Pin Description
VIN
1
DNC
2
DNC
3
CS
4
VIN
1
CS
2
GND
3
GATE
4
8
RT
7
DNC
6
VDD
5
DNC
16
DNC
15
DNC
14
RT
13
DNC
12
VDD
11
DNC
10
DNC
9
8-Lead SOIC
9.90x3.90mm body
1.75mm height (max)
1.27mm pitch
16-Lead SOIC
HV9801A
HV9801ALG-G
HV9801ANG-G
GND
5
DNC
6
DNC
7
GATE
8
-G indicates package is RoHS compliant (‘Green’)
DNC
8-Lead SOIC (LG)
16-Lead SOIC (NG)
Caution! DNC means Do Not Connect!
Absolute Maximum Ratings
Parameter
V
VIN
V
VDD
V
CS
, V
LD
, V
PWMD
, V
GATE
Junction temperature range
Storage temperature range
Continuous power dissipation
(T
A
= +25°C)
8-Lead SOIC
16-Lead SOIC
Value
470V
12V
-0.3V to (V
VDD
+0.3V)
-40°C to +150°C
-65°C to +150°C
650mW
1000mW
Product Marking
9801A
YWW
LLLL
Y = Last Digit of Year Sealed
WW = Week Sealed
L = Lot Number
= “Green” Packaging
Package may or may not include the following marks: Si or
8-Lead SOIC (LG)
Top Marking
YWW
HV9801ANG
LLLLLLLL
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.
Bottom Marking
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)
Electrical Characteristics
(Specifications are at T
A
= 25°C, V
VIN
= 15V unless otherwise noted)
Sym
Description
Input voltage
Input current
Supply current, OTP shutdown
Undervoltage lockout threshold
Undervoltage lockout hysteresis
Maximum input current, limited by
UVLO
T
-
G
T
-
G
Min
15
-
-
6.45
-
3.5
1.5
Typ
-
1
-
6.70
500
-
-
Max
450
2
500
7.10
-
-
-
Unit
V
mA
μA
V
mV
mA
mA
Conditions
---
---
Input
V
VIN
I
VIN
I
VIN,OT
V
UVLO
ΔV
UVLO
I
UVLO
---
V
VIN
rising
V
VIN
falling
T
A
= 25°C
T
A
= 125°C
VDD Regulator
Notes:
G
Not production tested; guaranteed by design or characterization.
T
Specifications apply over the full operating ambient temperature range of -40°C < T
A
< +125°C.
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
2
Tel: 408-222-8888
www.supertex.com
HV9801A
Electrical Characteristics
(Specifications are at T
Sym
V
VDD
ΔV
LINE
ΔV
DD(UV)
ΔV
LOAD
Description
Output voltage
Line regulation
V
DD
Voltage margin
Load regulation
-
-
T
-
A
= 25°C, V
VIN
= 15V unless otherwise noted)
Min
7.25
-
500
-
Typ
7.50
-
-
-
Max
7.75
1
-
100
Unit
V
V
mV
mV
Conditions
C
GATE
= 500pF; R
RT
= 226kΩ
V
IN
= 15 to 450V; C
GATE
= 500pF;
R
RT
= 226kΩ
ΔV
DD(UV)
= V
DD
- UVLO
I
VDD
= 0 to 1mA; C
GATE
= 500pF;
R
RT
= 226kΩ
---
---
V
VIN
falling below V
UVLO
---
---
---
V
CS
= V
CST
+ 30mV
LED current falls beyond this
duty cycle
---
V
CS
= V
CST
+ 30mV
---
C
S
= V
DD
R
RT
= 1MΩ
R
RT
= 226kΩ
V
GATE
= 0V
V
GATE
= V
DD
C
GATE
= 500pF
C
GATE
= 500pF
---
---
VDD Regulator
(cont.)
Switch Dimming
I
VDDX
V
UVLO
T
PL1
T
PL2
F
PWM
V
CST
T
LEB
T
ONX
D
MAX
V
CSH
T
DLY
T
SCH
T
ONX
Supply current after power loss
Undervoltage lockout during VIN
power loss
Power loss, qualification-time
Power loss, time to reset
PWM dimming frequency
Current sense threshold
Leading edge blanking time
Minimum on-time
Maximum duty cycle maintaining
regulation
Hiccup threshold
V
CS
high to GATE low delay
Hiccup time
Minimum on-time
T
-
-
G
-
T
T
-
-
-
-
-
-
-
236
110
-
80
-
3.5
7
1
1.2
250
-
-
-
700
-
-
-
-
256
260
760
-
μA
V
ms
s
kHz
mV
ns
ns
%
LED Current Regulator
Short Circuit Protection
-
-
-
-
-
-
-
-
440
-
750
-
-
180
-
430
mV
ns
μs
ns
T
OFF
Timer
T
OFF
Off-time
-
-
-
-
-
-
G
G
32
8.0
165
165
-
-
-
-
40
10
-
-
30
30
140
20
48
12
-
-
50
50
-
-
μs
GATE Driver
I
SRC
I
SINK
t
RISE
t
FALL
T
TRIP
ΔT
TRIP
Sourcing current
Sinking current
Rise time
Fall time
Trip temperature
Hysteresis
mA
mA
ns
ns
°C
°C
Over-temperature Protection
Notes:
G
Not production tested; guaranteed by design or characterization.
T
Specifications apply over the full operating ambient temperature range of -40°C < T
A
< +125°C.
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
3
Tel: 408-222-8888
www.supertex.com
HV9801A
Functional Block Diagram
VIN
VDD
CS
Leading
Edge
Blanking
250mV
GND
OTP
VDD Regulator
UVLO
Average
Current
Regulator
OR
Hiccup
440mV
AND
GATE
S
R
Q
Q
OFF
Time
Generator
RT
Current Mirror from VDD Rail
HV9801A
Current Control Performance
The control method of the HV9801A virtually eliminates the
regulation errors associated with peak current mode control-
lers, such as errors caused by: inductor tolerance; propa-
gation delay of the current sense comparator; tolerance in
the oscillator frequency or off-timer; and changes in line and
load voltage.
Fig. 1 compares the load regulation of the HV9801A and that
of a device with peak current control. The difference in load
regulation between the HV9801A and the HV9910B, a peak
current regulator, is clearly visible.
0.60
0.55
Current Control
Application Information
Continuous Conduction Mode
The HV9801A is designed for control of a buck converter
operating in continuous conduction mode.
CCM operation is characterized by converter operation with
non-zero inductor current throughout the switching cycle.
Such operation can be achieved by selection of the induc-
tance.
LED Current
The HV9801A regulates the LED current with an accuracy
far superior to that of competing peak current mode control-
lers.
Average LED current is set by the current sense resistor
RCS and the current regulator reference voltage :
V = (I) • (R)
250mV = (I
LED
) • (R
RCS
)
For example, a 2Ω resistor correponds to a 125mA (aver-
age) LED current.
Output Characteristics
HV9801A
V
IN
= 170VDC
LED Current, A
0.50
0.45
0.40
0.35
0.30
0.25
0
HV9910B
10
20
Output Voltage, V
30
40
50
60
Fig.1. Typical output characteristic of the HV9801A LED
driver.
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
4
Tel: 408-222-8888
www.supertex.com
HV9801A
Duty Cycle, Off-time, On-time, Inductor
Duty cycle
The duty cycle (D) is related to the load voltage (V
LED
) and
input voltage (V
BUS
) by the simple relation:
V
OUT
= (D) • (V
IN
)
V
LED
= (D) • (V
BUS
)
Off-time
The HV9801A employs constant off-time control. Operation
with constant off-time suppresses subharmonic oscillation.
Switching period and switching frequency are related to on-
time and off-time as follows:
T
SW
= (T
ON
+ T
OFF
)
F
SW
= 1 / T
SW
On-time is related to off-time and duty cycle as follows:
D = (T
ON
) / (T
ON
+ T
OFF
)
With a given T
OFF
, the HV9801A dynamically adjusts T
ON
to
regulate the LED current. Specifically, T
ON
adapts to the duty
cycle associated with given V
BUS
and V
LED
.
Off-time Programming
Off-time is programmed by the R
T
resistor:
T
OFF
= (A) • (R
RT
) + B
where A = 40ps / Ω and B = 300ns
For instance, a 200kΩ resistor corresponds to 8.3μs off-time.
An acceptable range for RT is 30kΩ to 1MΩ, corresponding
to an off-time range between 1.5µs and 40.3µs.
Inductor
The converter should operate in continuous conduction
mode. As such, the inductor current should not fall to zero
within a switching cycle, and inductor current ripple should
be sized accordingly.
A common choice for peak-to-peak Inductor current ripple
(PPR) is 30 to 40% of nominal LED current.
Inductance can be calculated from the current drop during
off-time:
(L) • (ΔI) = (V) • (ΔT)
(L) • (PPR) • (I
LED
) = (V
LED
) • (T
OFF
)
For instance, 30% PPR on 350mA average current equates
to 105mA ripple, which together with 5µs off-time, and 30V
LED string voltage corresponds to 1.43mH inductance.
A design with 30V LED voltage and with 150V bus voltage
corresponds to 20% duty cycle; respectively, with a 120V
bus voltage to 25% duty cycle. 20% duty cycle corresponds
to 1.25µs on-time, 25% duty cycle corresponds to 1.67µs.
Hence, the switching frequency is 167kHz at 150V bus volt-
age and 150kHz at 120V bus voltage.
Maximum Duty Cycle
Duty cycle should be limited to the specified maximum
(80%). Accordingly, the LED string voltage and the bus volt-
age are limited to the same ratio. Operation at a larger duty
cycle results in an LED current lower than programmed.
Minimum Duty Cycle
Duty cycle is limited on the low side by the minimum on-time
specification (760ns). Operation at a smaller on-time causes
the LED current to exceed the programmed value.
LED string voltage can not be made arbitrarily low. Minimum
LED voltage can be determined from the following:
D
MIN
= (T
ONX
) / (T
OFF
+ T
ONX
)
V
LED
= (D
MIN
) • (V
BUS
)
For instance, with 5µs off-time, the duty cycle should be kept
above 13%. Such a duty cycle corresponds to an LED string
voltage of 19.5V at 150V bus voltage.
A design requiring a lower LED string voltage requires
change to a longer off-time.
Short Circuit Protection
A rise of the LED current sense signal above 440mV (176%
of nominal) trips the short circuit comparator thereby caus-
ing the converter to switch to hiccup mode. In hiccup mode,
off-time is lengthened to about 750µs to allow the inductor
current to drop to a safe level.
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
5
Tel: 408-222-8888
www.supertex.com
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