MCP1664
High-Voltage Step-Up LED Driver with UVLO and Open Load Protection
Features
•
•
•
•
36V, 400 m Integrated Switch
Up to 92% Efficiency
Drive LED Strings in Constant Current
1.8A Peak Input Current Limit:
- I
LED
up to 200 mA at 3.3V V
IN
, 4 White LEDs
- I
LED
up to 300 mA at 5.0V V
IN
, 4 White LEDs
- I
LED
up to 150 mA at 4.2V V
IN
, 8 White LEDs
Input Voltage Range: 2.4V to 5.5V
Undervoltage Lockout (UVLO):
- UVLO at V
IN
Rising: 2.3V, typical
- UVLO at V
IN
Falling: 1.85V, typical
Shutdown Current (EN = GND): 40 nA Typical
PWM Operation: 500 kHz Switching Frequency
Cycle-by-Cycle Current Limiting
Internal Compensation
Open Load Protection (OLP) in the event of:
- Feedback Pin Shorted to GND (Prevent
Excessive Current into LEDs)
- Disconnected LED String (Prevent
Overvoltage to the Converter’s Output and
SW Pin)
Overtemperature Protection
Available Packages:
- 5-Lead SOT-23
- 8-Lead 2x3 TDFN
General Description
The MCP1664 is a compact, space-efficient,
fixed-frequency, non-synchronous step-up converter
optimized to drive multiple strings of LEDs with
constant current powered from two and three-cell
alkaline or NiMH/NiCd as well as from one-cell Li-Ion or
Li-Polymer batteries.
The device integrates a 36V, 400 m low-side switch,
which is protected by the 1.8A cycle-by-cycle inductor
peak current limit operation. The MCP1664 starts up
without high inrush current or output overshoot. All
compensation and protection circuitry is integrated to
minimize the number of external components.
The internal feedback (V
FB
) voltage is set to 300 mV for
low power dissipation when sensing and regulating the
LED current. A single resistor sets the LED current.
The device features an UVLO which avoids start-up
with low inputs or discharged batteries for two
cell-powered applications.
The MCP1664 features an open load protection (OLP)
which turns off the operation in situations when the
LED string is accidentally disconnected or the feedback
pin is short-circuited to GND.
While in Shutdown mode (EN = GND), the device stops
switching, and consumes 40 nA typical of input current.
•
•
•
•
•
•
•
•
•
Package Types
MCP1664
SOT-23
Applications
• Two and Three-Cell Alkaline or NiMH/NiCd White
LED Driver for Backlighting Products
• Li-Ion Battery LED Lightning Application
• Camera Flash
• LED Flashlights and Backlight Current Source
• Medical Equipment
• Portable Devices:
- Hand-Held Gaming Devices
- GPS Navigation Systems
- LCD Monitors
- Portable DVD Players
SW 1
GND 2
V
FB
3
4 EN
5 V
IN
MCP1664
2x3 TDFN*
V
FB
1
S
GND
2
SW 3
NC 4
EP
9
8
7
6
5
EN
P
GND
NC
V
IN
* Includes Exposed Thermal Pad (EP); see
Table 3-1.
2015 Microchip Technology Inc.
DS20005408A-page 1
MCP1664
Typical Application
L
4.7 – 10 µH
D
MBRM140
LED1
V
IN
2.4V – 3.0V
ALKALINE
+
C
IN
4.7 – 30 µF
V
IN
I
LED
=
MCP1664
EN
ON
ALAKLINE
+
OFF
GND
V
FB
V
FB
= 0.3V
I
LED
= 25 mA
R
SET
12
0.3V
R
SET
LED6
SW
LED2
C
OUT
10 µF
V
OUT
Max. 32V
-
-
L = 4.7 µH for maximum 4 white LEDs
L = 10 µH for 5 to 10 white LEDs
C
IN
= 4.7 – 10 µF for V
IN
> 2.5V
C
IN
= 20 – 30 µF for V
IN
< 2.5V
Maximum LED Current in Regulation vs. Input Voltage, T
A
= +25°C
350
300
250
I
OUT
(mA)
200
150
8 wLEDs, L = 10 µH
4 wLEDs, L = 4.7 µH
100
50
0
2
2.5
3
3.5
4
V
IN
(V)
4.5
5
5.5
DS20005408A-page 2
2015 Microchip Technology Inc.
MCP1664
1.0
ELECTRICAL
CHARACTERISTICS
†
Notice:
Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of
the device at those or any other conditions above those
indicated in the operational sections of this
specification is not intended. Exposure to maximum
rating conditions for extended periods may affect
device reliability.
Absolute Maximum Ratings †
V
SW
– GND .....................................................................+36V
EN, V
IN
– GND...............................................................+6.0V
V
FB
...............................................................................+0.35V
Power Dissipation ....................................... Internally Limited
Storage Temperature ....................................-65°C to +150°C
Ambient Temperature with Power Applied ....-40°C to +125°C
Operating Junction Temperature...................-40°C to +150°C
ESD Protection On All Pins:
HBM ................................................................. 4 kV
MM ..................................................................400V
DC AND AC CHARACTERISTICS
Electrical Specifications:
Unless otherwise specified, all limits apply for typical values at ambient temperature
T
A
= +25°C, V
IN
= 3.3V, V
OUT
loaded with 3 white LEDs (V
F
= 2.65V at I
F
= 100 mA), I
LED
= 20 mA,
C
IN
= C
OUT
= 10 µF, X7R ceramic, L = 4.7 µH.
Boldface
specifications apply over the controlled T
A
range of -40°C to +125°C.
Parameters
Input Voltage Range
Undervoltage Lockout (UVLO)
Maximum Output Voltage
Maximum Output Current
Sym.
V
IN
UVLO
START
UVLO
STOP
V
OUTmax
I
OUT
Min.
2.4
—
—
—
—
Typ.
—
2.3
1.85
—
150
200
300
Feedback Voltage Reference
Feedback Input Bias Current
Shutdown Quiescent Current
NMOS Peak Switch Current
Limit
NMOS Switch Leakage
V
FB
I
VFB
I
QSHDN
I
N(MAX)
I
NLK
275
—
—
—
—
300
0.025
0.04
1.8
0.4
Max.
5.5
—
—
32
—
—
—
325
—
—
—
—
Units
V
V
V
V
mA
mA
mA
mV
µA
µA
A
µA
EN = GND
Note 2
V
IN
= V
SW
= 5V;
V
OUT
= 5.5V
V
EN
= V
FB
= GND
V
IN
= 5V,
I
LED
= 100 mA,
4 series white LEDs
Note 2
V
IN
= 3.3V to 5V
Note 2
±15%
Conditions
Note 1
V
IN
rising, I
LED
= 20 mA
V
IN
falling, I
LED
= 20 mA
Note 1
4.2V V
IN
, 8 LEDs
3.3V V
IN
, 4 LEDs
5.0V V
IN
, 4 LEDs
NMOS Switch ON Resistance
R
DS(ON)
—
0.4
—
Feedback Voltage Line
Regulation
Maximum Duty Cycle
Switching Frequency
EN Input Logic High
EN Input Logic Low
EN Input Leakage Current
Note 1:
|(V
FB
/V
FB
)/V
IN
|
DC
MAX
f
SW
V
IH
V
IL
I
ENLK
—
—
425
85
—
—
0.5
90
500
—
—
0.025
1
—
575
—
7.5
—
%/V
%
kHz
% of V
IN
% of V
IN
µA
V
EN
= 5V
2:
Minimum input voltage in the range of V
IN
(V
IN
< 5.5V < V
OUT
) depends on the maximum duty cycle
(DC
MAX
) and on the output voltage (V
OUT
), according to the boost converter equation:
V
INmin
= V
OUT
x (1 – DC
MAX
). Output voltage is equal to the LED voltage plus the voltage on the sense
resistor (V
LED
+ V_R
SET
). Recommended (V
OUT
- V
IN
) > 1V.
Determined by characterization, not production tested.
2015 Microchip Technology Inc.
DS20005408A-page 3
MCP1664
DC AND AC CHARACTERISTICS (CONTINUED)
Electrical Specifications:
Unless otherwise specified, all limits apply for typical values at ambient temperature
T
A
= +25°C, V
IN
= 3.3V, V
OUT
loaded with 3 white LEDs (V
F
= 2.65V at I
F
= 100 mA), I
LED
= 20 mA,
C
IN
= C
OUT
= 10 µF, X7R ceramic, L = 4.7 µH.
Boldface
specifications apply over the controlled T
A
range of -40°C to +125°C.
Parameters
Start-Up Time
Sym.
t
SS
Min.
—
Typ.
100
Max.
—
Units
s
Conditions
EN Low to High,
90% of I
LED
(Note
2, Figure 2-10)
Note 2
Note 2
Thermal Shutdown Die
Temperature
Die Temperature Hysteresis
Note 1:
T
SD
T
SDHYS
—
—
150
20
—
—
°C
°C
2:
Minimum input voltage in the range of V
IN
(V
IN
< 5.5V < V
OUT
) depends on the maximum duty cycle
(DC
MAX
) and on the output voltage (V
OUT
), according to the boost converter equation:
V
INmin
= V
OUT
x (1 – DC
MAX
). Output voltage is equal to the LED voltage plus the voltage on the sense
resistor (V
LED
+ V_R
SET
). Recommended (V
OUT
- V
IN
) > 1V.
Determined by characterization, not production tested.
TEMPERATURE SPECIFICATIONS
Electrical Specifications:
Unless otherwise specified, all limits apply for typical values at ambient temperature
T
A
= +25°C, V
IN
= 3.0V, I
OUT
= 20 mA, V
OUT
= 12V, C
IN
= C
OUT
= 10 µF, X7R ceramic, L = 4.7 µH.
Boldface
specifications apply over the air-forced T
A
range of -40°C to +125°C.
Parameters
Temperature Ranges
Operating Junction Temperature
Range
Storage Temperature Range
Maximum Junction Temperature
Package Thermal Resistances
Thermal Resistance, 5L SOT-23
Thermal Resistance, 8L 2x3 TDFN
JA
JA
—
—
201.0
52.5
—
—
°C/W
°C/W
T
J
T
A
T
J
-40
-65
—
—
—
—
+125
+150
+150
°C
°C
°C
Steady State
Sym.
Min.
Typ.
Max.
Units
Conditions
DS20005408A-page 4
2015 Microchip Technology Inc.
MCP1664
2.0
Note:
TYPICAL PERFORMANCE CURVES
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
with
4
white
LEDs
Note:
Unless otherwise indicated: V
IN
= 3.3V, I
LED
= 20 mA, V
OUT
loaded
(V
F
= 2.9V at I
F
= 100 mA), C
IN
= C
OUT
= 10 µF, X7R ceramic, L = 4.7 µH.
160
140
LED Current (mA)
120
Efficiency (%)
R
SET
= 2.1
100
90
80
R
SET
= 3
V
IN
= 5.5V
100
80
60
40
20
0
2.3
2.7
3.1
70
60
50
40
30
20
10
0
0
50
V
IN
= 3.0V
V
IN
= 4.0V
R
SET
= 6
R
SET
= 15.2
3.5 3.9 4.3 4.7
Input Voltage (V)
5.1
5.5
100
150
200
I
LED
(mA)
250
300
350
FIGURE 2-1:
V
IN
.
160
140
LED Current (mA)
120
Four White LEDs, I
LED
vs.
FIGURE 2-4:
vs. I
LED
.
100
90
80
Efficiency (%)
Four White LEDs, Efficiency
R
SET
= 2.1
V
IN
= 5.5V
V
IN
= 4.0V
V
IN
= 3.0V
100
80
60
40
20
0
-40 -25 -10
5
R
SET
= 3
70
60
50
40
30
20
10
0
0
50
R
SET
= 6
R
SET
= 15.2
8 x wLED
L = 10 µH
20 35 50 65 80 95 110 125
Ambient Temperature (
o
C)
100
150
I
LED
(mA)
200
250
FIGURE 2-2:
Four White LEDs, I
LED
vs.
Ambient Temperature.
160
140
8 x wLED, L = 10μH, V
IN
= 4.2V
R
SET
= 2.1
FIGURE 2-5:
vs. I
LED
.
400
350
LED Current (mA)
300
250
Eight White LEDs, Efficiency
LED Current (mA)
120
100
80
60
40
20
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
Ambient Temperature (
o
C)
R
SET
= 15.2
R
SET
= 6
R
SET
= 3
5 wLEDs, L = 10µH
200
150
100
50
0
2.3
2.7
3.1
4 wLEDs, L = 4.7µH
8 wLEDs, L = 10 µH
3.5 3.9 4.3
Input Voltage (V)
4.7
5.1
5.5
FIGURE 2-3:
Eight White LEDs, I
LED
vs.
Ambient Temperature.
FIGURE 2-6:
Maximum I
LED
vs. V
IN
.
2015 Microchip Technology Inc.
DS20005408A-page 5
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