MP4689A
100V Input, 1A,
High-Power LED Driver
DESCRIPTION
FEATURES
The MP4689A is a high-voltage input, stepdown, switching regulator that delivers up to 1A
of constant current to high-power LEDs. The
MP4689A integrates a high-side, high-voltage,
power MOSFET with a typical current limit of
3.5A.
The wide 4.5V to 100V input range
accommodates a variety of step-down
applications, making it ideal for automotive,
industrial, and general lighting applications.
Hysteresis current-mode control is applied for
very fast response, which makes the 20kHz
dimming frequency possible. MPS’s proprietary
feedback control scheme minimizes the number
of external components while delivering an LED
current with ±3% accuracy.
The switching frequency is up to 1MHz, which
allows for a small component size. Thermal
shutdown and short-circuit protection (SCP)
provide reliable and fault-tolerant operations. A
170µA quiescent current allows the MP4689A
to be used in battery-powered applications.
The MP4689A is available in a SOIC-8 package
with an exposed pad.
Wide 4.5V to 100V Operating Input Range
No Output Capacitor Required
±3% LED Current Accuracy
Hysteretic Control: No Compensation
Up to 1MHz Switching Frequency
Up to 20kHz Dimming Frequency
Dedicated PWM Dimming Control Input
Short-Circuit Protection (SCP) with
Integrated High-Side MOSFET
Thermal Shutdown
200mV Reference Voltage for High
Efficiency
Up to 95% Efficiency
170μA Quiescent Current
Available in a SOIC-8 Package with an
Exposed Pad
APPLICATIONS
High-Power LED Drivers
Automotive, Industry, and General Lighting
Constant Current Sources
All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For
MPS green status, please visit the MPS website under Quality
Assurance. “MPS” and “The Future of Analog IC Technology” are registered
trademarks of Monolithic Power Systems, Inc.
TYPICAL APPLICATION
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
1
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
ORDERING INFORMATION
Part Number
Package
Top Marking
MP4689AGN
SOIC-8 EP
See Below
*For Tape & Reel, add suffix-Z (e.g. MP4689AGN-Z)
TOP MARKING
MP4689A: Part number
LLLLLLLL: Lot number
MPS: MPS prefix
Y: Year code
WW: Week code
PACKAGE REFERENCE
SOIC-8 EP
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance (4)
Supply voltage (VIN) .................. -0.3V to +100V
Switch voltage (VSW) ........... -0.5V to VIN + 0.5V
BST to SW ..................................... -0.3V to +6V
All other pins .................................. -0.3V to +6V
Junction temperature ............................... 150°C
Continuous power dissipation (TA = +25°C) (2)
..................................................................2.5W
Lead temperature .................................... 260°C
Storage temperature ................ -65°C to +150°C
SOIC-8 EP ............................ 50 ....... 10 ... °C/W
Recommended Operating Conditions (3)
Supply voltage (VIN) ....................... 4.5V to 95V
EN and DIM voltages ........................... 0V to 5V
Operating junction temp.(TJ) .... -40°C to +125°C
θJA
θJC
NOTES:
1) Exceeding these ratings may damage the device.
2) The maximum allowable power dissipation is a function of the
maximum junction temperature TJ(MAX), the junction-toambient thermal resistance θJA, and the ambient temperature
TA. The maximum allowable continuous power dissipation at
any ambient temperature is calculated by PD(MAX)=(TJ(MAX)TA)/θJA. Exceeding the maximum allowable power dissipation
produces an excessive die temperature, causing the regulator
to go into thermal shutdown. Internal thermal shutdown
circuitry protects the device from permanent damage.
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7 4-layer board.
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
2
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
ELECTRICAL CHARACTERISTICS
Typical values are at TJ = +25°C, unless otherwise noted. Minimum and maximum values are at
TJ = -40°C ~ +125°C, unless otherwise noted. Guaranteed by characterization.
Parameter
VIN UVLO threshold
VIN UVLO hysteresis
Shutdown supply current
Quiescent supply current
Upper switch on resistance (5)
Upper switch leakage current
Current limit
EN up threshold
EN threshold hysteresis
EN input current
EN sinking current
DIM up threshold
DIM threshold hysteresis
DIM input current
Symbol
DIM on propagation delay (5)
tDIMDH
DIM off propagation delay (5)
tDIMDL
Feedback voltage threshold high (5)
VFBH
Feedback voltage threshold low (5)
VFBL
FB input current
FB propagation delay to output
high (5)
FB propagation delay to output low
(5)
Thermal shutdown
RDS(ON)
ISWLK
IPK
VENH
VENHY
IENI
IENS
VDIMH
VDIMHY
IDIM
IFB
tFBDH
tFBDL
TSD
Condition
Min
3.6
VEN = 0V
No load, VFB = 250mV
VBST - VSW = 5V
VEN = 0V, VSW = 0V
VFB = 0.15V
1.38
VEN = 5V
VEN = 2V
0.8
VDIM = 5V or 0V
VFB = 0V, VDIM rising edge to
VSW rising edge
VFB = 0V, VDIM falling edge to
VSW falling edge
4.5V < VIN < 100V, VFB
rising from 0V until VSW <
30V
4.5V < VIN < 100V, VFB
falling from 0.25V until VSW >
30V
VFB = 5V or 0V
Falling edge of VFB from
0.25V to 0V to VSW rising
edge
Rising edge of VFB from 0V
to 0.25V to VSW falling edge
Hysteresis = 20°C
Typ
4.0
0.4
2
170
500
0.01
3.5
1.55
320
0.01
2
1.15
300
-1
Max
4.35
15
240
1
1.78
1
3
1.5
1
Units
V
V
µA
µA
mΩ
µA
A
V
mV
µA
µA
V
mV
µA
50
ns
50
ns
215
mV
185
mV
-300
300
nA
100
ns
100
ns
150
°C
NOTE:
5) Guaranteed by design.
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
3
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
PIN FUNCTIONS
SOIC-8 EP
Pin #
1
2
3
4
5
6
7
8
Name
Description
Feedback. FB is the input to the hysteretic comparators. An external current sensing
resistor is connected in series with the LEDs to GND. The feedback voltage is
connected to FB and is regulated at +200mV with a 15% current ripple.
No connection.
NC
Input supply. VIN supplies power to all of the internal control circuities, both BST
VIN
regulators, and the high-side switch. A decoupling capacitor to ground must be placed
close to VIN to minimize switching spikes.
Bootstrap. BST is the positive power supply for the internal floating high-side MOSFET
BST
driver. Connect a bypass capacitor between BST and SW.
Switch node. SW is the output from the high-side switch. A low VF Schottky rectifier to
SW
ground is required. The rectifier must be close to SW to reduce switching spikes.
PWM dimming input. Pull DIM below the specified threshold for dimming off; pull DIM
DIM
above the specified threshold for dimming on. If there is no need for the dimming
function, connect DIM to EN.
Enable input. Pull EN below the specified threshold to shut the chip down; pull EN
EN
above the specified threshold or leave EN floating to enable the chip.
Ground. GND should be connected as close to the output capacitor as possible while
GND,
Exposed avoiding the high-current switch paths. Connect the exposed pad to the GND plane for
Pad
optimal thermal performance.
FB
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
4
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
TYPICAL PERFORMANCE CHARACTERISTICS
L = 47μH, 1 LED Load, TA = 25°C, unless otherwise noted.
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
5
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
BLOCK DIAGRAM
Figure 1: Functional Block Diagram
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
6
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
OPERATION
Hysteresis Current Control with Adaptive
Threshold Adjustment
The MP4689A operates in hysteresis current
control mode to regulate the LED current
accurately. FB is the sensed voltage of the LED
current across the sensing resistor. The power
MOSFET is turned on and remains on until FB
rises to 215mV. The power MOSFET is turned
off and remains off until FB falls to 185mV. The
two thresholds of 215mV and 185mV are
adjusted adaptively to compensate for all circuit
delays. Therefore, the LED current is regulated
very accurately with a 200mV average value at
FB.
Enable Control (EN)
The MP4689A has a dedicated enable control
pin (EN) with positive logic. Its falling threshold
is a precise 1.2V, and its rising threshold is
1.5V (300mV higher).
When floating, EN is pulled up to about 3.0V by
an internal 1µA current source and is enabled.
To pull EN down, a current capability over 1µA
is needed.
Floating Driver and Bootstrap Charging
The floating power MOSFET driver is powered
by an external bootstrap capacitor. This floating
driver has its own UVLO protection. This
UVLO’s rising threshold is 2.2V with a
hysteresis of 150mV.
The bootstrap capacitor is charged and
regulated to about 5V by the dedicated internal
bootstrap regulator.
Under-Voltage Lockout (UVLO)
Under-voltage lockout (UVLO) is implemented
to protect the chip from operating at an
insufficient supply voltage. The UVLO rising
threshold is about 4.0V, while its falling
threshold is a consistent 3.65V.
Thermal Shutdown
Thermal shutdown is implemented to prevent
the chip from operating at exceedingly high
temperatures. When the silicon die temperature
is higher than its upper threshold, the entire
chip shuts down. When the temperature is
lower than its lower threshold, the chip is
enabled again.
LED Short Protection
The LED current is well-regulated with the FB
voltage at 200mV. As long as the LED sensing
resistor has not failed, the output current is
within the limitation. If the LED sensing resistor
has failed or the output is shorted to GND
directly, the FB voltage is low, even if the power
MOSFET is turned on. The power MOSFET
shuts off if the failure time is longer than 10µs.
The MP4689A attempts operation again after
about 300μs.
The power MOSFET current is also accurately
sensed via a current sense MOSFET. If the
current is over 3.5A, the IC shuts down. This
offers extra protection under output short
conditions.
In case the internal circuit does not have
sufficient voltage and the bootstrap capacitor is
not well charged, extra external circuitry can be
used to ensure that the bootstrap voltage is in
its normal operational region. Refer to the
External Bootstrap Diode section on page 9 for
details.
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
7
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
APPLICATION INFORMATION
Setting the LED Current
The LED current (ILED) is set using a sensing
resistor (RFB), which is in series with the LEDs
and connected to GND. The voltage on RFB is
connected to FB and can be calculated with
Equation (1):
ILED
VFB
RFB
(1)
For example, for a 700mA LED current, RFB is
287mΩ.
Inductor Selection and Frequency Setting
The inductor (LO) is required to supply a
constant current to the LED. The inductor value
is related to the switching frequency (fS) setting,
which can be calculated with Equation (2):
VOUT (VIN VOUT )
fs
VIN (8 108 VIN L 15% ILED )
(2)
Where VIN is the input voltage, and VOUT is the
output voltage to drive the LEDs. A larger-value
inductor results in a smaller switching
frequency. The peak inductor current can be
calculated with Equation (3):
ILP ILED (
4 108 VIN
1.075)
L ILED
(3)
Choose an inductor that will not saturate under
the maximum inductor peak current and has a
switching frequency under 2MHz.
Output Rectifier Diode
The output rectifier diode supplies current to the
inductor when the high-side switch is off. To
reduce losses due to the diode forward voltage
and recovery times, use a Schottky diode.
The RMS current through the diode can be
calculated with Equation (4):
ID ILED 1
VOUT
VIN
(4)
Input Capacitor (CIN)
The input current to the step-down converter is
discontinuous and therefore requires a
capacitor to supply AC current to the step-down
converter while maintaining the DC input
voltage. Use low ESR capacitors for the best
performance, especially for high switching
frequency applications.
The RMS current through the input capacitor
can be calculated with Equation (5):
ID ILED
VOUT
VIN
(5)
With low ESR capacitors, estimate the input
voltage ripple with Equation (6):
VIN
V
V
ILED
OUT 1 OUT
fs CIN VIN
VIN
(6)
Choose an input capacitor with enough RMS
current rating and enough capacitance for small
input voltage ripples.
When electrolytic or tantalum capacitors are
applied, a small, high-quality ceramic capacitor
(i.e.: 0.1μF) should be placed as close to the IC
as possible.
Output Capacitor (COUT)
The output capacitor (COUT) is not necessary for
the MP4689A. The LED current ripple (peak-topeak value) is about 15% of the LED DC
current. An output capacitor can be used to
reduce the LED current ripple further. Low ESR
capacitors are recommended to keep the output
voltage ripple low so that the AC ripple current
through the LEDs is small. The output voltage
ripple can be estimated with Equation (7):
VOUT
VOUT
V
1 OUT
fS LO
VIN
1
RESR
8
f
C
S
OUT
(7)
Where RESR is the equivalent series resistance
(ESR) value of the output capacitor.
Choose a diode with a maximum reverse
voltage rating greater than the maximum input
voltage and a current rating greater than the
maximum diode current.
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
8
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
External Bootstrap Diode
An external bootstrap diode may enhance the
efficiency of the LED driver (see Figure 2). An
external BST diode is recommended from the
floating driver power to BST in the following
cases:
There is a 5V rail available in the system.
VIN is no greater than 5V.
VOUT is between 3.3V and 5V.
This diode is also recommended for high duty
cycle operation (when VOUT / VIN > 65%) and
very high frequency (over 1.5MHz) applications.
The bootstrap diode can be a low-cost one,
such as IN4148 or BAT54.
Figure 2: External Bootstrap Diode
PCB Layout Recommendation
It is essential to place the input decoupling
capacitor, catch diode, and the MP4689A (VIN,
SW, and PGND) as close to each other as
possible with very short and fairly wide traces.
This helps reduce the voltage spike on the SW
node greatly and lowers EMI noise level. For
best results, follow the guidelines below.
1. Run the feedback trace as far from the
inductor and noisy power traces as
possible.
2. Run the feedback trace on the side of the
PCB opposite of the inductor with a ground
plane separating the two.
3. Create a grid of thermal vias right under the
exposed pad to help improve thermal
conduction.
4. Use small vias (15mil barrel diameter) so
that the hole is essentially filled up during
the plating process, aiding conduction to the
other side.
A hole that is too large can cause solder
wicking problems during the reflow
soldering process. The pitch (distance
between the centers) of several such
thermal vias in an area is typically 40mil.
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
9
MP4689A – 100V INPUT, 1A, HIGH-POWER LED DRIVER
PACKAGE INFORMATION
SOIC-8 EP
NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third
party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not
assume any legal responsibility for any said applications.
MP4689A Rev. 1.0
www.MonolithicPower.com
2/17/2017
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
2017 MPS. All Rights Reserved.
10
工商网监
湘ICP备2023018690号
