HV9911 [SUPERTEX]
Switch-mode LED Driver IC with High Current Accuracy; 开关模式LED驱动器IC，具有高电流精度
| 型号： | HV9911 |
| 厂家： | 
Supertex, Inc |
| 描述： | Switch-mode LED Driver IC with High Current Accuracy |
| 文件： | 总9页 (文件大小：450K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
HV9911
Initial Release
Switch-mode LED Driver IC with High Current Accuracy
Features
General Description
►
Switch mode controller for single switch drivers
The HV9911 is a current mode control LED driver IC designed to
control single switch PWM converters (buck, boost or buck-boost),
in a constant frequency or constant off-time mode. The controller
uses a peak current control scheme, (with programmable slope
compensation), and includes an internal transconductance amplifier
to control the output current in closed loop, enabling high output
current accuracy (in the case of buck and buck-boost converters,
the high side output current can be sensed by using the HV7800).
In the constant frequency mode, multiple HV9911s can by
synchronized to each other, or to an external clock, using the SYNC
pin. Programmable MOSFET current limit enables current limiting
during input under voltage and output overload conditions. The IC
also includes a 0.25A source and 0.5A sink gate driver for high power
applications. An internal 9 to 250V linear regulator powers the IC,
eliminating the need for a separate power supply for the IC. HV9911
provides a TTL compatible, PWM dimming input that can accept an
external control signal with a duty ratio of 0-100% and a frequency
of up to a few kilohertz.
o Buck
o Boost
o Buck-boost
►
►
►
►
Works with high side current sensing
Closed loop control of output current
High PWM dimming ratio
Internal 9 to 250V linear regulator (can be extended
using external zener diodes)
Internal 2% Voltage Reference (-40°C<TA<85°C)
Constant frequency or constant off-time operation
Programmable slope compensation
Enable & PWM dimming
+0.25A/-0.5A gate drive (VDD = 10V)
Output short circuit protection
Output over voltage protection
Synchronization capability
Programmable MOSFET current limit
Soft start
►
►
►
►
►
►
►
►
►
►
The HV9911 based LED driver is ideal for RGB backlight applications
with DC inputs. The HV9911 based LED Lamp drivers can achieve
efficiency in excess of 90% for buck and boost applications.
Applications
►
►
►
►
RGB backlight applications
Automotive LED driver application
Battery Powered LED lamps
Other DC/DC LED drivers
Typical Application Circuit
VIN
L1
CIN
D1
CO
CDD
ROVP1
VIN
RT
VDD
RT
GND
Q1
ROVP2
PWMD
SC
GATE
CS
RSLOPE
RCS
RSC
HV9911
SYNC
REF
OVP
CREF
FAULT
Q2
RL2
CLIM
FDBK
RL1
IREF
COMP
RS
RR1
CC
RR2
NR011206
1
HV9911
Pin Assignment
Ordering Information
Package Options
16-Lead SOIC
HV9911NG-G
FDBK
IREF
1
2
3
4
5
6
7
8
VIN
16
15
14
13
12
11
10
9
DEVICE
VDD
HV9911
GATE
GND
CS
COMP
-G indicates package is RoHS compliant (‘Green’)
HV9911PWMD
OVP
SC
FAULT
REF
RT
SYNC
CLIM
Absolute Maximum Ratings
Parameter
Value
VIN to GND
-0.5V to +250V
VDD to GND
-0.3V to +13.5V
-0.3V to (VDD + 0.3V)
-0.3V to (VDD + 0.3V)
-0.3V to (VDD + 0.3V)
-0.3V to (VDD + 0.3V)
CS1, CS2 to GND
PWMD to GND
GATE to GND
All other pins to GND
Continuous Power Dissipation (TA = +25°C)
16-Pin SOIC (derate 6.3mW/°C above +25°C)
Operating Temperature Range
Junction Temperature
Storage Temperature Range
630mW
-40°C to +85°C
+125°C
-65°C to +150°C
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.
NR011206
2
HV9911
Electrical Characteristics
(Over recommended operating conditions, VIN = 24V, TA = 25°C, unless otherwise specified)
Symbol Parameter
Input
Min
Typ
Max
Units Conditions
VINDC
IINSD
Internal Regulator
Input DC supply voltage range*
9
-
-
250
1.5
V
DC input voltage
PWM_D connected to GND, VIN = 24V
Shut-Down mode supply current*
1.0
mA
VIN = 9–250V, IDD(ext) = 0,
VDD
Internally regulated voltage*
DD undervoltage lockout threshold
7.25
7.75
8.25
V
PWMD connected to GND
UVLO
V
6.65
-
6.90
500
7.20
-
V
VDD rising
---
∆UVLO
VDD undervoltage lockout hysteresis
mV
Steady State External Voltage
which can applied at the VDD pin1
VDD(ext)
-
-
12
V
---
Reference
REF bypassed with a 0.1µF capacitor to GND;
IREF= 0; VDD = 7.75V; PWMD = GND
VREF
REF pin voltage*
1.225 1.25 1.275
V
REF bypassed with a 0.1µF capacitor to GND;
IREF = 0; VDD = 7.25 – 12V; PWMD = GND
VREFLINE
Line regulation of reference voltage
0
0
-
-
20
10
mV
mV
Load regulation of reference
voltage
REF bypassed with a 0.1µF capacitor to GND;
VREFLOAD
IREF = 0 - 500µA; PWMD = GND
PWM Dimming
VPWMD(lo)
VPWMD(hi)
RPWMD
GATE
ISOURCE
ISINK
PWMD input low voltage*
-
-
-
0.80
-
V
V
VDD = 7.25V – 12V
VDD = 7.25V – 12V
VPWMD = 5.0V
PWMD input high voltage*
PWMD pull-down resistance
2.0
50
100
150
kΩ
GATE short circuit current
GATE sinking current
GATE output rise time
GATE output fall time
0.2
0.4
-
-
A
A
VGATE = 0V; VDD = 7.75V
VGATE = 7.75V ; VDD = 7.75V
CGATE = 1nF; VDD = 7.75V
CGATE = 1nF; VDD = 7.75V
-
-
-
TRISE
50
25
85
45
ns
ns
TFALL
-
Over Voltage Protection
VOVP
IC Shut down voltage*
1.215
1.25 1.285
V
VDD = 7.25 – 12V ; OVP rising
Current Sense
TBLANK
Leading Edge Blanking
100
-
-
-
375
180
ns
ns
---
OP = VDD ; CLIM = REF;
CSENSE = 0 to 600mV step
TDELAY1
Delay to Output of OP comparator
Delay to Output of CLIMIT
comparator
OP = VDD ; CLIM = 300mV ;
CSENSE = 0 to 400mV step
TDELAY2
VOFFSET
-
-
-
180
10
ns
Comparator Offset voltage
-10
mV
---
NR011206
3
HV9911
Symbol Parameter
Min
Typ
Max
Units Conditions
Internal Transconductance Opamp
GB
Gainbandwidth product#
Open Loop DC Gain
Input common-mode range#
Output Voltage Range#
Transconductance
-
1.0
-
MHz 75pF capacitance at OP pin
AV
66
-
-
-
dB
V
Output Open
---
VCM
-0.3
0.7
340
-3.0
-
3.0
6.75
530
3.0
1.0
VO
-
-
VDD = 7.75V
gm
435
-
µA/V ---
VOFFSET
IBIAS
Input Offset Voltage
Input bias current#
mV
nA
---
---
0.5
Oscillator
fOSC, MIN
fOSC, MAX
DMAX
Minimum Oscillator frequency*
Maximum Oscillator frequency*
Maximum Duty cycle
22
25
350
90
10
-
28
392
-
kHz
kHz
%
RT = 3.65MΩ
RT = 261kΩ
---
308
-
-
IOUTSYNC
IINSYNC
Sync output current
20
µA
µA
---
Sync input current
0
200
VSYNC < 0.1V
Output Short Circuit
Propagation time for short circuit
NI=200mV ; INV=450mV;
FAULT goes from high to low
TOFF
-
-
250
ns
detection
TRISE,FAULT Fault output rise time
TFALL,FAULT Fault output fall time
-
-
-
-
300
200
2.2
ns
ns
1nF capacitor at FAULT pin
1nF capacitor at FAULT pin
NI=200mV
GFAULT
Amplifier gain at NI pin
1.8
2
Soft Start
Current into CLIM pin when pulled
low
FAULT is low ;
6.25k resistor between REF and CLIM
ICLIM
-
-
200
µA
Slope Compensation
ISLOPE
Current Sourced out of SLOPE pin
0
-
100
2.2
µA
-
---
ISLOPE = 50µA ; RCSENSE = 1kΩ
GSLOPE
Internal Current Mirror ratio
1.8
2
1 Parameters are not guaranteed to be within specifications if the external V voltage is greater than VDD(ext)
* Specifications which apply over the full operating ambient temperature ranDgDe of -40°C < TA < +85°C.
# Guaranteed by design
NR011206
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HV9911
Pin Assignment
FDBK
IREF
1
2
3
4
5
6
7
8
VIN
16
15
14
13
12
11
10
9
VDD
GATE
GND
CS
COMP
HV9911PWMD
OVP
SC
FAULT
REF
RT
SYNC
CLIM
Pin Description
Pin #
Pin
Description
This pin is the input of a 9 – 250V high voltage regulator.
1
VIN
This is a power supply pin for all internal circuits. It must be bypassed with a low ESR capacitor to GND
(at least 0.1uF).
2
VDD
3
4
GATE
GND
This pin is the output gate driver for an external N-channel power MOSFET.
Ground return for all circuits. This pin must be connected to the return path from the input.
This pin is used to sense the drain current of the external power FET. It includes a built-in 100ns (min)
blanking time.
5
6
CS
SC
Slope compensation for current sense. A resistor between SC and GND will program the slope
compensation. In case of constant off-time mode of operation, slope compensation is unnecessary and
the pin can be left open.
This pin sets the frequency or the off-time of the power circuit. A resistor between RT and GND will
program the circuit in constant frequency mode. A resistor between RT and GATE will program the circuit
in a constant off-time mode.
7
RT
This I/O pin may be connected to the SYNC pin of other HV9911 circuits and will cause the oscillators to
lock to the highest frequency oscillator.
8
9
SYNC
CLIM
This pin provides a programmable input current limit for the converter. The current limit can be set by using
a resistor divider from the REF pin. Soft start can also be provided using this pin.
This pin provides 2% accurate reference voltage. It must be bypassed with at least a 10nF capacitor to
GND
10
REF
This pin is pulled to ground when there is an output short circuit condition or output over voltage condition.
This pin can be used to drive an external MOSFET in the case of boost converters to disconnect the load
from the source
11
12
FAULT
OVP
This pin provides the over voltage protection for the converter. When the voltage at this pin exceeds 1.25V,
the gate output of the HV9912 is turned off and FAULT goes low. The IC will turn on when the power is
recycled
When this pin is pulled to GND (or left open), switching of the HV9911 is disabled. When an external TTL
high level is applied to it, switching will resume
13
14
PWMD
COMP
Stable Closed loop control can be accomplished by connecting a compensation network between COMP
and GND
The voltage at this pin sets the output current level. The current reference can be set using a resistor
divider from the REF pin
15
16
IREF
FDBK
This pin provides output current feedback to the HV9911 by using a current sense resistor
NR011206
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HV9911
Functional Block Diagram
V
VIN
REF
bg
Linear Regulator
POR
VDD
GATE
_
+
CLIM
SS
Blanking
100ns
FAULT
+
_
CS
R
S
Q
1:2
+
ramp
R
S
POR
_
Q
Q
_
+
V
bg
OVP
SC
SS
+
_
FDBK
G
_
+
m
13R
R
SYNC
RT
IREF
One Shot
COMP
SS
2
PWMD
GND
Functional Description
Power Topology
Continuous mode buck and boost converters are ideal as external circuits connected at the VDD and VREF pins. This
LED drivers, as they can achieve high efficiencies greater linear regulator can be turned off by overdriving the VDD pin
than 90%. The HV9911 is a switch-mode converter LED using an external bootstrap circuit at voltages higher than
driver designed to control a continuous conduction mode 8.25V (up to 12V). The input voltage range of the IC can be
buck or boost in a constant frequency (or constant off-time) increased to 450V by putting a 200V zener in series with the
mode. The IC includes an internal linear regulator, which IC at the VIN pin.
operates from input voltages of 9V to 250V eliminating the
need for an external power supply for the IC. The IC includes Although this linear regulator can power the IC by itself, at
features typically required in LED drivers like open LED higher input voltages and/or higher operating temperatures,
protection, output short circuit protection, linear and PWM it might be necessary to supply power using an external
dimming, programmable input current limiting and accurate bootstrap circuit as the excessive power dissipation in the IC
control of the LED current. A high current gate drive output might cause the IC to fail. This would also result in improved
enables the controller to be used in high power converters.
efficiencies for the overall circuit. Dropping the input voltage
across an external zener diode would also help to divert the
power dissipation away from the IC.
Linear Regulator
The V pin of the IC should be bypassed with at least a
0.1µF,DlDow ESR capacitor.
The built in linear regulator operates from input voltages of
9V to 250V and provides a 7.75V voltage at the VDD pin. This
7.75V is used to power the IC and also provide the power to
NR011206
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HV9911
Reference
Current Sense
HV9911 includes a 2% accurate, 1.25V reference, which can The current sense input of the HV9911 includes a built in
be used as the reference for the output current as well as 100ns (minimum) blanking time to prevent spurious turn off
to set the switch current limit. This reference is also used due to the initial current spike when the FET turns on.
internally to set the over voltage protection threshold. The
reference is buffered so that it can deliver a maximum of The HV9911 includes two high-speed comparators – one is
500µA external current to drive the external circuitry. The used during normal operation and the other is used to limit
reference should be bypassed with at least a 10nF low ESR the maximum input current during input under voltage or
capacitor.
overload conditions.
The IC includes an internal resistor divider network, which
steps down the voltage at the COMP pin by a factor of
15. This stepped-down voltage is given to one of the
comparators as the current reference. The reference to the
other comparator, which acts to limit the maximum inductor
current, is given externally.
Oscillator
The oscillator can be set in two ways. Connecting the
oscillator resistor between the RT and GATE pins will
program the off-time. Connecting the resistor between RT
and GND will program the time period.
It is recommended that the sense resistor RCS be chosen so
as to provide about 250mV current sense signal.
In both cases, resistor RT sets the current, which charges
an internal oscillator capacitor. The capacitor voltage ramps
up linearly and when the voltage increases beyond the Current Limit
internal set voltage, a comparator triggers the SET input of
the internal SR flip-flop. This starts the next switching cycle. Current limit has to be set by a resistor divider from the
The time period of the oscillator can be computed as:
1.25V reference available on the IC. Assuming a maximum
operating inductor current i (including the ripple current),
the maximum voltage at the pCk LIM pin can be set as:
Ts ≈ RT ×11pF
5× Rsc
Rslope
VCLIM ≥ 1.2× Ipk × Rcs +
×0.9
Slope Compensation
For converters operating in the constant frequency mode,
slope compensation becomes necessary to ensure stability
of the peak current mode controller, if the operating duty
cycle is greater than 0.5. Choosing a slope compensation
which is one half of the down slope of the inductor current
ensures that the converter will be stable for all duty cycles.
Note that this equation assumes a current limit at 120%
of the maximum input current. Also, if VCLIM is greater than
450mV, the saturation of the internal opamp will determine
the limit on the input current rather than the C pin. In such
a case, the sense resistor RCS should be reLdIMuced till VCLIM
reduces below 450mV.
Slope compensation can be programmed by two resistors
inSdLuOPcEtor currSeCnt, the slope compensation resistors can be
It is recommended that no capacitor be connected between
CLIM and GND. If necessary, the capacitor value must be
chosen to be less than 1000pF.
R
and R . Assuming a down slope of DS (A/µs) for the
computed as:
10 × RSC
Rslope
=
DS ×106 ×Ts × Rcs
FAULT protection
A typical value for Rsc is 499Ω.
The HV9911 has built-in output over-voltage protection
and output short circuit protection. Both protection features
Note: The maximum current that can be sourced out of the are latched, which means that the power to the IC must
SC pin is limited to 100µA. This limits the minimum value be recycled to reset the IC. The IC also includes a FAULT
of the R
resistor to 25kΩ. If the equation for slope pin which goes low during any fault condition. At startup, a
compensSaLtOioPEn produces a value of RSLOPE less than this monoshot circuit, (triggered by the POR circuit), resets an
value, then RSC would have to be reduced accordingly. It is internal flip-flop which causes FAULT to go high, and remains
recommended that RSLOPE be chosen in the range of 25kΩ high during normal operation. This also allows the gate drive
- 50kΩ.
to function normally. This pin can be used to drive an external
disconnected switch (Q2 in the Typical Boost Application
Circuit on pg.1), which will disconnect the load during a
fault condition. This disconnect switch is very important in a
boost converter, as turning off the switching FET (Q1) during
NR011206
7
HV9911
an output short circuit condition will not remove the fault (Q1 When synchronized in this manner, a permanent HIGH
is not in the path of the fault current). The disconnect switch or LOW condition on the SYNC pin will result in a loss of
will help to disconnect the shorted load from the input.
synchronization, but the HV9911 based converters will
continue to operate at their individually set operating
frequency. Since loss of synchronization will not result in total
system failure, the SYNC pin is considered fault tolerant.
Over Voltage Protection
Over voltage protection is achieved by connecting the output
voltage to the OVPpin through a resistive divider. The voltage Internal 1MHz Transconductance Amplifier
at the OVP pin is constantly compared to the internal 1.25V.
When the voltage at this pin exceeds 1.25V, the IC is turned HV9911 includes a built in 1MHz transconductance amplifier,
off and FAULT goes low.
with tri-state output, which can be used to close the feedback
loop. The output current sense signal is connected to the
FDBK pin and the current reference is connected to the IREF
pin.
Output Short Circuit Protection
The output short circuit condition is indicated by FAULT. At
startup, a monoshot circuit, (triggered by the POR circuit),
resets an internal flip-flop, which causes FAULT to go high,
and remains high during normal operation. This also allows
the gate drive to function normally.
The output of the opamp is controlled by the signal applied
to the PWMD pin. When PWMD is high, the output of the
opamp is connected to the COMP pin. When PWMD is low,
the output is left open. This enables the integrating capacitor
to hold the charge when the PWMD signal has turned off
the gate drive. When the IC is enabled, the voltage on the
integrating capacitor will force the converter into steady state
almost instantaneously.
The steady state current is reflected in the reference
voltage connected to the transconductance amplifier.
The instantaneous output current is sensed from the INV
terminal of the amplifier. The short circuit threshold current is
internally set to 200% of the steady state current.
The output of the opamp is buffered and connected to the
current sense comparator using a 15:1 divider. The buffer
helps to prevent the integrator capacitor from discharging
during the PWM dimming state.
During short circuit condition, when the current exceeds the
internally set threshold, the SR flip-flop is set and FAULT
goes low. At the same time, the gate driver of the power FET
is inhibited, providing a latching protection. The system can
be reset by cycling the input voltage to the IC.
Linear Dimming
Linear dimming can be accomplished by varying the voltage
at the I
pin, as the output current is proportional to the
Note: The short circuit FET should be connected before the
current sense resistor as reversing RS and Q2 will affect the
accuracy of the output current (due to the additional voltage
drop across Q2 which will be sensed).
voltageRaEFt the IREF pin. This can be done either by using a
potentiometer from the REF pin or by applying an external
voltage source at the IREF pin.
Note that due to the offset voltage of the transconductance
opamp, pulling the I pin very close to GND will cause the
internal short circuit RcEoFmparator to trigger and shut down the
IC. This limits the linear dimming range of the IC. However,
a 1:10 linear dimming range can be easily obtained. It is
recommended that the PWMD pin be used to get zero output
current rather than pull the IREF pin to GND.
Synchronization
The SYNC pin is an input/output (I/O) port to a fault tolerant
peer-to-peer and/or master clock synchronization circuit.
For synchronization, the SYNC pins of multiple HV9911
based converters can be connected together and may also
be connected to the open drain output of a master clock.
When connected in this manner, the oscillators will lock
to the device with the highest operating frequency. When
synchronizing multiple ICs, it is recommended that the same
timing resistor be (corresponding to the switching frequency)
be used in all the HV9911 circuits.
PWM Dimming
PWM dimming can be achieved by driving the PWMD pin
with a TTL compatible square wave source. The PWM
signal is connected internally to the three different nodes
– the transconductance amplifier, the FAULT output, and the
GATE output.
In rare occasions, given the length of the connecting lines for
the SYNC pins, a resistor between SYNC and GND may be
required to damp any ringing due to parasitic capacitances.
It is recommended that the resistor chosen be greater than
300kΩ.
When the PWMD signal is high, the GATE and FAULT pins
are enabled, and the output of the transconductance opamp
is connected to the external compensation network. Thus,
NR011206
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HV9911
the internal amplifier controls the output current. When the discontinuous, and a very large output capacitor is required
PWMD signal goes low, the output of the transconductance to reduce the ripple in the LED current. Thus, this capacitor
amplifier is disconnected from the compensation network. will have a significant impact on the PWM dimming response.
Thus, the integrating capacitor maintains the voltage across By turning off the disconnect switch when PWMD goes low,
it. The GATE is disabled, so the converter stops switching the output capacitor is prevented from being discharged,
and the FAULT pin goes low, turning off the disconnect and thus the PWM dimming response of the boost converter
switch.
improves dramatically.
The output capacitor of the converter determines the Note that disconnecting the capacitor might cause a sudden
PWM dimming response of the converter, since it has to spike in the capacitor voltage as the energy in the inductor
get charged and discharged whenever the PWMD signal is dumped into the capacitor. This might trigger the OVP
goes high or low. In the case of a buck converter, since the comparator if the OVP point is set too close to the maximum
inductor current is continuous, a very small capacitor is used operating voltage. Thus, either the capacitor has to sized
across the LEDs. This minimizes the effect of the capacitor slightly larger or the OVP set point has to be increased.
on the PWM dimming response of the converter. However,
in the case of a boost converter, the output current is
16-LEAD SO PACKAGE (NG) (NARROW BODY)
0.3895 0.0045
(9.8935 0.1145)
0.2335 0.0105
(5.931 0.267)
0.156 0.002
(3.962 0.051)
0.193 0.012
(4.9022 0.3048)
0.500
(12.700)
0.350
(8.890)
TYP.
TYP.
0.0255 0.0005
(0.6475 0.0125)
0.013 0.004
(0.3302 0.1016)
7° (4 PLCS)
45°
0.065 0.004
(1.651 0.102)
0.009 0.002
(0.216 0.038)
0° - 8 °
7° (4 PLCS)
0.059 0.002
(1.499 0.051)
0.006 0.002
(0.1524 0.0508)
0.033 0.017
(0.8382 0.4318)
0.0275 0.0025
(0.6985 0.0635)
0.020 0.002
(0.508 0.0508)
0.0165 0.0035
(0.4191 0.0889)
0.050
(1.270)
TYP.
Dimensions in Inches
(Dimensions in Millimeters)
Measurement Legend =
Doc.# DSFP - HV9911
NR011206
9
相关型号：
HV9918K7-G
LED Driver, 1-Segment, 3 X 3 MM, 0.80 MM HEIGHT, 0.65 MM PITCH, GREEN, MO-229WEEC-2, DFN-8
SUPERTEX
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