MP2340
24V, 2A, 1MHz Synchronous
Step-Down LED Driver
The Future of Analog IC Technology
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PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
DESCRIPTION
FEATURES
The MP2340 is a 24V monolithic synchronous
step-down white LED driver with a built-in power
MOSFET and rectifier. It achieves up to 2A
continue output current with excellent load and
line regulation. Peak current mode operation
provides fast transient response and eases loop
stabilization.
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The MP2340 incorporates both analog and
PWM dimming onto a single control pin. The
chip can implement deep analog dimming and
PWM dimming.
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The MP2340 requires a minimum number of
readily available standard external components
and is available in TSOT23-6 package.
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TYPICAL APPLICATION
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Fault condition protection includes cycle-by-cycle
peak current limiting, output short circuit
protection, open LED protection and thermal
shutdown.
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4.2V to 24V Wide Input Range
Synchronous Step-Down Converter
100mΩ Internal High-side Power MOSFET
80mΩ Internal Low-side Synchronous
Rectifier
Peak Current Mode Control
Up to 2A Continue Output Current
100mV Feedback Voltage
Up to 97% Efficiency
Fixed 1MHz Switching Frequency
Analog & PWM Dimming
Cycle-by-Cycle Current Limit
Inherent LED Open Protection
Output Short Circuit Protection
Thermal Shutdown
Auto-Restart Function
Available in TSOT23-6 Package
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APPLICATIONS
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Infrared LED Driver
General LED Driver
Flashlight
Handheld Computers Backlight
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All MPS parts are lead-free, halogen free, and adhere to the RoHS
directive. For MPS green status, please visit MPS website under Quality
Assurance.
“MPS” and “The Future of Analog IC Technology” are Registered
Trademarks of Monolithic Power Systems, Inc.
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VIN (V)
MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
1
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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ORDERING INFORMATION
Part Number
MP2340GJ
Package
TSOT23-6
Top Marking
See Below
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* For Tape & Reel, add suffix –Z (e.g. MP2340GJ–Z).
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TOP MARKING
AUB: product code of MP2340GJ;
Y: year code;
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PACKAGE REFERENCE
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TSOT23-6
Thermal Resistance
Supply Voltage VIN ....................................... 26V
VSW ........................................ –0.3V to VIN +0.3V
VBST ...................................................... VSW + 6V
All Other Pins .................................–0.3V to +6V
Continuous Power Dissipation (TA = 25°C) (2)
TSOT23-6 ................................................ 1.25W
Junction Temperature ...............................150°C
Lead Temperature ....................................260°C
Storage Temperature.............. –65°C to +150°C
ESD Capability Human Body Mode .......... 2.0kV
TSOT23-6 ..............................100 ..... 55 ... °C/W
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Recommended Operating Conditions
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(3)
Supply Voltage VIN ...........................4.2V to 24V
Operating Junction Temp. (TJ)…-40ºC to 125°C
(4)
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ABSOLUTE MAXIMUM RATINGS (1)
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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 will cause excessive die temperature, and the
regulator will 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 PCB.
MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
2
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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ELECTRICAL CHARACTERISTICS
Typical values are VIN = 12V, TJ = 25°C, unless otherwise noted.
Minimum and maximum values are at VIN = 12V, TJ = -40°C to +125°C, unless otherwise noted,
guaranteed by characterization.
Parameters
Supply Voltage
Operating Range
Turn On Threshold
Hysteretic Voltage
Supply Current
Shutdown Current
Quiescent Current
Enable & Dimming
EN/DIM OFF Threshold
EN/DIM ON Threshold
Turn Off Delay Time
EN/DIM Pull-Up Current
Symbol
Condition
VIN
VIN_ON
VIN_HYS
After turn on
VIN rising edge
ISD
IQ
VEN_OFF
VEN_ON
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VEN/DIM falling edge
VEN/DIM rising edge
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tOFF_DELAY
IEN/DIM
VADIM_MAX
Min Analog Dimming Threshold
Feedback
VADIM_MIN
VEN = 0V
Theoretically,
VFB = 100mV
VFB = 5mV
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VFB
4.2V ≤ VIN ≤ 24V
Burst Mode Allowable Threshold
VFB_BURST_AL
Burst Mode Recovery Hysteresis (5) VFB_BURST_HYS
Feedback Current
IFB
VFB = 150mV
Power Switch
VIN = 5.0V
High-Side MOSFET OnRDS(ON)_H
Resistance
VIN = 4.2V
VIN = 5.0V
Low-Side Sync-Rectifier Switch
RDS(ON)_L
On-Resistance
VIN = 4.2V
Switch Leakage
ISW_LKG
VEN = 0V, VSW = 0V
When high-side switch
High-Side Current Limit
ILIMIT_H
turn-on
When low-side switch
Low-Side Current Limit
ILIMIT_L
turn-on
Both for high-side & lowOCP Current Threshold
IOCP
side
Oscillator Frequency
fSW
VFB = 80mV
Maximum Duty Cycle
DMAX
VFB = 80mV
Minimum On-Time
tON_MIN
Restart Timer
Hiccup Timer at Fault Condition
tSTART
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Max
Units
4.2
3.5
0.08
3.7
0.12
24
4
0.24
V
V
V
10
0.9
50
1.1
μA
mA
0.27
0.55
16
2.8
0.31
0.59
22
3.8
0.35
0.63
28
5.3
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V
ms
μA
1.31
1.44
1.57
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Typ
VEN = 0V
VEN = 2V, VFB = 200mV
Max Analog Dimming Threshold
Feedback Voltage
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Min
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0.7
0.78
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100
107
mV
112
10
126
65
mV
mV
nA
100
110
80
90
170
180
140
150
1
mΩ
mΩ
mΩ
mΩ
μA
3.5
5
6.6
A
-950
-600
-350
mA
3.5
5.5
7
A
0.8
90
1
94
70
1.2
MHz
%
ns
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0.63
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2.4
MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
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MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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ELECTRICAL CHARACTERISTICS (continued)
Typical values are VIN = 12V, TJ = 25°C, unless otherwise noted.
Minimum and maximum values are at VIN = 12V, TJ = -40°C to +125°C, unless otherwise noted,
guaranteed by characterization.
Parameters
Bootstrap
Symbol
Condition
Bias Voltage for High-Side Driver
VBST-VSW
5.5V≤VIN≤24V
VIN =4.2V
Thermal Shutdown
Thermal Shutdown Threshold (6)
Thermal Shutdown Hysteresis (6)
TSD
THYS
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4.8
3.6
5.1
150
60
Max
Units
5.5
V
V
°C
°C
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Typ
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Notes:
5) Guaranteed by design.
6) Guaranteed by characterization.
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MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
4
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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TYPICAL CHARACTERISTICS
Feedback Voltage vs.
Junction Temperature
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102
High-Side MOSFET OnResistance vs.Junction
Temperature
Low-Side Rectifier OnResistance vs. Junction
Temperature
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140
VFB (mV)
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140
100
VIN=4.2V
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100
97
VIN=5V
80
96
95
-50 -25 0
25 50 75 100 125 150
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60
-50 -25 0
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100
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VIN=5V
60
40
-50 -25 0
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VIN=4.2V
80
25 50 75 100 125 150
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120
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160
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25 50 75 100 125 150
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MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
5
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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TYPICAL PERFORMACE CHARACTERISTICS
Performance waveforms are tested on the evaluation board.
VIN=12V, 2 WLEDs in series, VOUT=5.9V, ILED=1.5A, L=4.7μH, TA = 25°C, unless otherwise noted.
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0.6
0.4
0.2
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-0.2
-0.4
-0.6
-0.8
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0.0
-0.8
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-1.2
-1.6
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0.6
0.0
0.2 0.4 0.6 0.8
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1.2
1.0
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-0.4
1.4
0.2
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0.4
1.6
0.4
0 1 2 3 4 5 6 7 8 9 10 11
0.8
0 1 2 3 4 5 6 7 8 9 10 11
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1.2
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1.6
1.2 1.4 1.6
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MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
6
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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TYPICAL PERFORMACE CHARACTERISTICS (continued)
Performance waveforms are tested on the evaluation board.
VIN=12V, 2 WLEDs in series, VOUT=5.9V, ILED=1.5A, L=4.7μH, TA = 25°C, unless otherwise noted.
Steady State
VIN Start-Up
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IL
500mA/div.
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VIN
5V/div.
IL
500mA/div.
ILED
500mA/div.
IL
500mA/div.
VIN
2V/div.
VSW
5V/div.
VSW
10V/div.
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EN Start-Up
VEN
1V/div.
IL
500mA/div.
ILED
500mA/div.
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VSW
10V/div.
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VIN
5V/div.
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VOUT
2V/div.
IL
200mA/div.
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VEN/DIM=0.6V
ILED
20mA/div.
VEN/DIM
200mV/div.
IL
500mA/div.
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VSW
5V/div.
Short LED+ to LEDProtection
IL
500mA/div.
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VSW
10V/div.
Minimum Analog Dimming
IL
500mA/div.
ILED
500mA/div.
VEN
1V/div.
VSW
10V/div.
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ILED
500mA/div.
EN Shutdown
Open LED Protection
VIN
2V/div.
VSW
5V/div.
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ILED
500mA/div.
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VIN Shutdown
Short LED+ to GND
Protection
IL
1A/div.
VFB
50mV/div.
VSW
5V/div.
VSW
5V/div.
MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
7
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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PIN FUNCTIONS
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Pin #
Name
Description
1
GND
Ground. This pin is the voltage reference for the regulated output voltage. For this reason
care must be taken in its layout.
2
SW
Switch Output.
3
VIN
Supply Voltage. The MP2340 operates from a 4.2V to 24V unregulated input. Input capacitor
is needed to prevent large voltage spikes from appearing at the input.
4
FB
Current Sense Feedback Voltage. Its internal reference voltage is 0.1V.
5
6
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Bootstrap. A capacitor is connected between SW and BST pins to form a floating supply
across the power switch driver. This capacitor is needed to drive the power switch’s gate
above the supply voltage.
BST
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On/Off Control Input & Dimming Command Input. Leave EN/DIM floating or a voltage
higher than 0.59V on this pin turns on the chip. For analog dimming, when the EN/DIM voltage
EN/DIM rises up from 0.7V to 1.44V, the output current changes from min value to the full-scale LED
current. To apply PWM dimming, apply a 100Hz to 2kHz PWM signal with amplitude higher
than 1.6V to this pin.
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MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
8
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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FUNCTION BLOCK DIAGRAM
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Figure 1: Functional Block Diagram
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MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
9
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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OPERATION
The MP2340 is a high frequency synchronous
rectified step-down switching mode LED driver
with built-in internal power MOSFET and
synchronous rectifier switch. It offers a very high
performance solution to achieve up to 2A
continuous output LED current over a wide input
supply range with excellent load and line
regulation.
The MP2340 operates in a fixed 1MHz frequency,
peak current control mode to regulate the output
current. A new switching cycle is initiated by the
internal clock at the beginning of every switching
cycle. The integrated high-side power MOSFET
is turned on and the inductor current rises linearly
to provide the energy to the load. The high-side
power MOSFET remains on until its current hits
the value of the COMP level which is the output
of the internal error amplifier. The output voltage
of error amplifier depends on the difference of
output feedback and the internal high precision
reference and it decides how much energy
should be transferred to the load. The high-side
power switch remains off until the next clock
cycle starts. After the high-side switch is off, the
low-side sync-switch is on and the inductor
current flows through the low-side switch. In
order to avoid shoot-through issue, the dead time
is inserted to avoid the high-side and low-side
FETs to turn on at the same time. By maximum
duty cycle limit, when the duty cycle of one
switching period reaches 94%, the current in the
high-side power MOSFET does not reach the
COMP set current value, the high-side power
MOSFET is forced to turn off.
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Under-voltage lockout (UVLO) is implemented to
avoid the chip from operating at insufficient
supply voltage. The MP2340 UVLO comparator
monitors the output voltage of the internal
regulator, which is supplied from VIN.
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If both VIN and EN/DIM are higher than their
appropriate thresholds, the chip starts. The
reference block starts first to generate stable
reference voltages and currents, then the internal
regulator is enabled. The regulator provides
stable supply for the remaining circuitries.
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Error Amplifier
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The internal low offset error amplifier compares
the FB voltage with the internal 100mV reference
and outputs COMP voltage, which is inside of the
chip and used to control the high-side MOSFET
peak current and then to regulate the output
current.
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Under-Voltage
Lockout
(UVLO)
Startup/Shutdown Procedure
Three events can shut down the chip: EN/DIM
keeps low for more than tOFF_DELAY, VIN drops
below UVLO and thermal shutdown. In shutdown
procedure, the signaling path is first blocked to
avoid any fault triggering. The COMP voltage and
the internal supply rail are then pulled down.
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The soft start is implemented to prevent the
converter output current from overshooting
during start up. When the chip starts, the internal
circuitry generates a soft-start voltage (SS)
ramping up from 0V. The soft-start period lasts
until the voltage on the soft-start capacitor
exceeds the 0.1V reference voltage. At this point
the reference voltage takes over.
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Floating Driver and Bootstrap Charging
The high-side floating power MOSFET driver is
powered by an external bootstrap capacitor. The
bootstrap capacitor voltage is regulated internally.
At normal operation, a 5.1V bootstrap voltage is
maintained between BST and SW.
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Internal Soft-Start
Enable Control
EN/DIM is a control pin that turns the regulator
on/off and dims the output LED current. Leave
this pin floating or drive it high to turn on the
MP2340. After the pin is pulled down to low for
tOFF_DELAY (typical 22ms), the MP2340 is turned
off. Figure 2 shows the control logic of the
EN/DIM pin.
Figure 2: EN/DIM Time Sequence
MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
10
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
the output voltage rises up very close to the input
Analog Dimming
voltage. Every power component operates at a
Apply DC signal on EN/DIM can dim the MP2340
safe state.
on the analog dimming mode. When the voltage
on EN/DIM is lower than VADIM_MIN, the LED
LED Short Circuit Protection
current is regulated to the minimal scale. When
The MP2340 integrates the LED Short Circuit
the voltage on EN/DIM is between VADIM_MIN and
Protection circuitry. There are several features
VADIM_MAX, the LED current changes from the
preventing the MP2340 from damage when the
minimal scale to the full scale of LED current. If
LED short circuit occurs.
the voltage on EN/DIM pin is higher than
The MP2340 features a cycle-by-cycle current
VADIM_MAX, the maximum LED current is regulated.
limit to restrict the maximum current of the
Figure 3 shows the Analog Dimming Curve. Due
inductor. And a protection mechanism monitors
to the hysteretic of EN/DIM ON/OFF Threshold,
FB level though an internal RC filter. Once it rises
at VEN/DIM falling edge, the chip maintains at
up to hit VFB_BURST_AL, the chip stops switching
minimal LED current longer until VEN/DIM is lower
until FB level drops to a lower value, and the
than VEN_OFF. The dimming curve is absolutely
system works in burst mode.
same in linear dimming range.
In the worst case, LED Short Circuit to GND, if
the cycle-by-cycle current limit function can not
clamp the current overshoot sufficiently, the
current (thru both the high-side and low-side
FETs) is also monitored by over-current detector
inside the chip. If it is higher than the short circuit
threshold (IOCP), the MP2340 treats it as a short
circuit condition.
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Figure 3: Analog Dimming Curve
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When Over Current Condition or Short Circuit
Condition is detected, the MP2340 turns off the
high-side and low-side MOSFETs both for 2.4ms,
then restart again. During this period, the COMP
voltage is pulled down to ground, so the restart
from the fault condition is also with soft-start.
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PWM Dimming
Thermal Shutdown
Apply PWM signal on EN/DIM to implement
PWM dimming mode. The dimming frequency is
recommended in the range of 100Hz to 2kHz to
achieve a good dimming linearity. The digital
signal’s amplitude must be higher than 1.6V.
Thermal shutdown is implemented to prevent the
chip from operating at exceeding high
temperature. When the silicon die temperature is
higher than 150°C, the OTP shuts down the
whole chip. When the temperature is lower than
its lower threshold, typically 90°C, the chip
restarts again.
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Open LED
N
If LED is open without feedback signal, the
MP2340 works at the maximum duty cycle and
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MP2340 Rev. 0.8
www.MonolithicPower.com
10/19/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
Preliminary Specifications Subject to Change
© 2015 MPS. All Rights Reserved.
11
MP2340 – 24V, 2A, 1MHZ SYNCHRONOUS STEP-DOWN LED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
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APPLICATION INFORMATION
Setting LED Current
Selecting the Input Capacitor
The current sense resistor is inserted between
the anode of LED and GND. The current sense
resistor value is calculated as:
The input capacitor reduces the surge current
drawn from the input supply and the switching
noise from the device. The input capacitor
impedance at the switching frequency should be
less than the input output source impedance of
the input source to prevent high frequency
switching current from passing through the input.
Ceramic capacitors with X5R or X7R dielectrics
are highly recommended because of their low
ESR and small temperature coefficients. For
most applications, a 10µF capacitor is sufficient.
0.1V
ILED
RS =
For 2A LED current output, choose RS = 50mΩ.
Selecting the Inductor
A
