ON NCP5007SNT1 Compact backlight led boost driver Datasheet

NCP5007
Compact Backlight LED
Boost Driver
The NCP5007 is a high efficiency boost converter operating in a
current control loop, based on a PFM mode, to drive White LEDs. The
current mode regulation allows a uniform brightness of the LEDs. The
chip has been optimized for small ceramic capacitors and is capable of
supplying up to 1.0 W output power.
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Features
•
•
•
•
•
•
•
•
•
•
•
•
Inductor Based Converter brings High Efficiency
Constant Output Current Regulation
2.7 to 5.5 V Input Voltage Range
Vout to 22 V Output Compliance Allows up to 5 LEDs to be Driven
in Series which Provides Automatic LED Current Matching
Built−in Output Overvoltage Protection
0.3 mA Standby Quiescent Current
Includes Dimming Function (PWM)
Enable Function Driven Directly from Low Battery Voltage Source
Thermal Shutdown Protection
All Pins are Fully ESD Protected
Low EMI Radiation
Pb−Free Package is Available
MARKING
DIAGRAM
5
5
1
TSOP−5
(SOT23−5, SCR59−5)
SN SUFFIX
CASE 483
DCLAYWG
G
1
DCL = Device Code
A
= Assembly Location
Y
= Year
W = Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
Typical Applications
• LED Display Back Light Control
• High Efficiency Step Up Converter
FB
1
GND
2
EN
3
U1
3
Vbat
EN
C1
5
1
Vout
GND
Device
GND
L1
22 mH
2
MBR0530
D5
D4
Vout
Package
Shipping †
TSOP−5
3000/Tape & Reel
TSOP−5
(Pb−Free)
3000/Tape & Reel
D1
4
FB
D6
NCP5007SNT1
NCP5007SNT1G
C2
1.0 mF
NCP5007
R1
4
ORDERING INFORMATION
4.7 mF
GND
Vbat
(Top View)
Vbat
Vbat
5
D3
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
D2
GND
GND
5.6 W
Figure 1. Typical Application
© Semiconductor Components Industries, LLC, 2006
March, 2006 − Rev. 4
1
Publication Order Number:
NCP5007/D
NCP5007
Thermal
Shutdown
Current Sense
Vbat
Vsense
EN
5
Vbat
4
Vout
2
GND
3
100 k
CONTROLLER
Q1
GND
FB
1
300 k
−
+
GND
+200 mV
Band Gap
Figure 2. Block Diagram
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2
NCP5007
PIN FUNCTION DESCRIPTION
Pin
Symbol
Type
Description
1
FB
ANALOG
INPUT
This pin provides the output current range adjustment by means of a sense resistor connected
to the analog control or with a PWM control. The dimming function can be achieved by applying
a PWM voltage technique to this pin (see Figure 29). The current output tolerance depends
upon the accuracy of this resistor. Using a "5% metal film resistor, or better, yields good output
current accuracy. Note: A built−in comparator switches OFF the DC−DC converter if the voltage
sensed across this pin and ground is higher than 700 mV typical.
2
GND
POWER
This pin is the system ground for the NCP5007 and carries both the power and the analog
signals. High quality ground must be provided to avoid spikes and/or uncontrolled operation.
Care must be observed to avoid high−density current flow in a limited PCB copper track so a
robust ground plane connection is recommended.
3
EN
DIGITAL
INPUT
This is an Active−High logic input which enables the boost converter. The built−in pulldown
resistor disables the device when the EN pin is left open. Note the logic switching level of this
input has been optimized to allow it to be driven from standard or 1.8 V CMOS logic levels.
The LED brightness can be controlled by applying a pulse width modulated signal to the enable
pin (see Figure 30).
4
Vout
POWER
This pin is the power side of the external inductor and must be connected to the external
Schottky diode. It provides the output current to the load. Since the boost converter operates in
a current loop mode, the output voltage can range up to +22 V but shall not exceed this limit.
However, if the voltage on this pin is higher than the OVP threshold (Over Voltage Protection)
the device enters a shutdown mode. To restart the chip, one must either apply a low to high logic
signal to the EN pin, or switch off the Vbat supply.
A capacitor must be used on Vout to avoid false triggering of the OVP (Overvoltage Protect)
circuit. This capacitor filters the noise created by the fast switching transients. In order to limit
the inrush current and still have acceptable startup time the capacitor value should range
between 1.0 mF and 8.2 mF max. To achieve high efficiency this capacitor should be ceramic
(ESR t 100 mW).
Care must be observed to avoid EMI through the PCB copper tracks connected to this pin.
5
Vbat
POWER
The external voltage supply is connected to this pin. A high quality reservoir capacitor must be
connected across pin 5 and Ground to achieve the specified output voltage parameters. A
4.7 mF/6.3 V, low ESR capacitor must be connected as close as possible across pin 5 and
ground pin 2. The X5R or X7R ceramic MURATA types are recommended.
The return side of the external inductor shall be connected to this pin. Typical application will
use a 22 mH, size 1210, to handle the 10 to 100 mA output current range. When the desired
output current is above 20 mA, the inductor shall have an ESR v1.5 W to achieve good
efficiency over the Vbat range. The output current tolerance can be improved by using a larger
inductor value.
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3
NCP5007
MAXIMUM RATINGS
Symbol
Value
Unit
Power Supply
Rating
Vbat
6.0
V
Output Power Supply Voltage Compliance
Vout
28
V
Digital Input Voltage
Digital Input Current
EN
−0.3 v Vin v Vbat +0.3
1.0
V
mA
2.0
200
kV
V
PD
RqJA
160
250
mW
°C/W
Operating Ambient Temperature Range
TA
−25 to +85
°C
Operating Junction Temperature Range
TJ
−25 to +125
°C
TJmax
+150
°C
Tstg
−65 to +150
°C
ESD Capability (Note 1)
Human Body Model (HBM)
Machine Model (MM)
VESD
TSOP5 Package
Power Dissipation @ TA = +85°C (Note 2)
Thermal Resistance, Junction−to−Air
Maximum Junction Temperature
Storage Temperature Range
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. This device series contains ESD protection and exceeds the following tests:
Human Body Model (HBM) "2.0 kV per JEDEC standard: JESD22−A114
Machine Model (MM) "200 V per JEDEC standard: JESD22−A115
2. The maximum package power dissipation limit must not be exceeded.
3. Latchup current maximum rating: "100 mA per JEDEC standard: JESD78.
4. Moisture Sensivity Level (MSL): 1 per IPC/JEDEC standard: J−STD−020A.
POWER SUPPLY SECTION (Typical values are referenced to Ta = +25°C, Min & Max values are referenced −25°C to +85°C ambient
temperature, unless otherwise noted.)
Rating
Pin
Symbol
Min
Typ
Max
Unit
Power Supply
4
Vbat
2.7
−
5.5
V
Output Load Voltage Compliance
5
Vout
22
24.5
−
V
Continuous DC Current in the Load
@ Vout = 3
LED, L = 22 mH, ESR < 1.5 W, Vbat = 3.6 V
5
Iout
50
−
−
mA
Standby Current @ Iout = 0 mA, EN = L, Vbat = 3.6 V
4
Istdb
−
0.45
−
mA
Standby Current @ Iout = 0 mA, EN = L, Vbat = 5.5 V
4
Istdb
−
1.0
3.0
mA
4
Toffmax
−
320
−
ns
Thermal Shutdown Protection
−
TSD
−
160
−
°C
Thermal Shutdown Protection Hysteresis
−
TSDH
−
30
−
°C
Inductor Discharging Time @ Vbat = 3.6 V, L = 22 mH, 3
Iout = 10 mA
LED,
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4
NCP5007
ANALOG SECTION (Typical values are referenced to Ta = +25°C, Min & Max values are referenced −25°C to +85°C ambient
temperature, unless otherwise noted.)
Pin
Symbol
Min
Typ
Max
Unit
High Level Input Voltage
Low Level Input Voltage
1
EN
1.3
−
−
−
−
0.4
V
EN Pull Down Resistor
1
REN
−
100
−
kW
Feedback Voltage Threshold
4
FB
170
200
230
mV
Output Current Stabilizes @ 5% time delay following a
DC−DC startup @ Vbat = 3.6 V, L = 22 mH, Iout = 20 mA
5
Ioutdly
−
100
−
ms
Internal Switch ON Resistor @ Tamb = +25°C
5
QRDSON
−
1.7
−
W
Rating
5. The overall tolerance depends upon the accuracy of the external resistor.
THEORY OF OPERATION
The DC−DC converter is designed to supply a constant
current to the external load, the circuit being powered from
a standard battery supply. Since the regulation is made by
means of a current loop, the output voltage will vary
depending upon the dynamic impedance presented by the
load.
Considering a high intensity LED, the output voltage can
range from a low of 6.4 V (two LED in series biased with a
low current), up to 22 V, the maximum the chip can sustain
continuously. The basic DC−DC structure is depicted in
Figure 3.
With a 22 V operating voltage capability, the power
device Q1 can accommodate a high voltage source without
any leakage current degradation.
Vbat
L1
22 mH
Vdsense
POR
4
D1
Vds
C2
RESET
LOGIC
CONTROL
Vdsense
GND
+
−
D4
GND
D5
ZERO_CROSSING
1.0 mF
TIME_OUT
D3
D2
Q1
R1
−
V(Ipeak)
1
+
R2
xR
C2
Vref
GND
Figure 3. Basic DC−DC Converter Structure
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5
GND
Vs
NCP5007
Basically, the chip operates with two cycles:
Cycle #1 : time t1, the energy is stored into the inductor
Cycle #2 : time t2, the energy is dumped to the load
The POR signal sets the flip−flop and the first cycle takes
place. When the current hits the peak value, defined by the
error amplifier associated with the loop regulation, the
First Startup
flip−flop resets, the NMOS is deactivated and the current is
dumped into the load. Since the timing is application
dependent, the internal timer limits the Toff cycle to 320 ns
(typical), making sure the system operates in a continuous
mode to maximize the energy transfer.
Normal Operation
Ipeak
IL
Iv
t1
0 mA
t2
t
Ids
0 mA
t
Io
0 mA
t
Figure 4. Basic DC−DC Operation
Based on the data sheet, the current flowing into the
inductor is bounded by two limits:
• Ipeak Value: Internally fixed to 350 mA typical
• Iv Value: Limited by the fixed Toff time built in the
chip (320 ns typical)
The system operates in a continuous mode as depicted in
Figure 4 and t1 & t2 times can be derived from basic
equations. (Note: The equations are for theoretical analysis
only, they do not include the losses.)
Of course, from a practical stand point, the inductor must
be sized to cope with the peak current present in the circuit
to avoid saturation of the core. On top of that, the ferrite
material shall be capable to operate at high frequency
(1.0 MHz) to minimize the Foucault’s losses developed
during the cycles.
The operating frequency can be derived from the
electrical parameters. Let V = Vo − Vbat, rearranging
Equation 1:
E + L * di
dt
ton + dI * L
E
(eq. 1)
Since toff is nearly constant (according to the 320 ns
typical time), the dI is constant for a given load and
inductance value. Rearranging Equation 5 yields:
Let E = Vbat, then:
t1 +
(Ip * Iv) * L
Vbat
(Ip * Iv) * L
t2 +
Vo * Vbat
(eq. 2)
ton +
(eq. 3)
ton +
t2 * (Vo * Vbat)
DI +
L
320e * 9 * (22 * 3.0)
+ 276 mA
22e * 6
V*dt
L
*L
E
(eq. 6)
Let E = Vbat, and Vopk = output peak voltage, then:
Since t2 = 320 ns typical and Vo = 22 V maximum, then
(assuming a typical Vbat = 3.0 V):
DImax +
(eq. 5)
(Vopk * Vbat) * dt
Vbat
(eq. 7)
Finally, the operating frequency is:
(eq. 4)
F+
1
ton ) toff
(eq. 8)
The output power supplied by the NCP5007 is limited to
one watt: Figure 5 shows the maximum power that can be
delivered by the chip as a function of the input voltage.
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6
NCP5007
1200
400
3 LED
1000
350
2 LED
Ipeak (mA)
4 LED
5 LED
300
250
400
200
200
Pout = f(Vbat) @ Rsense = 2.0 W
0
150
2
3
4
5
2
6
3
4
Vbat (V)
5
6
Vbat (V)
Test conditions: 5 LEDs in series, steady state operation
Figure 5. Maximum Output Power as a Function of
the Battery Supply Voltage
Figure 6. Typical Inductor Peak Current as a
Function of Vbat Voltage
120
2 LED
100
3 LED
80
Iout (mA)
Pout (mW)
800
600
L = 22μH
Rsense = 10W
TA = +25°C
4 LED
60
5 LED
40
20
0
2.5
3.0
3.5
4.0
Vbat (V)
4.5
5.0
5.5
Test conditions: L = 22 mH, Rsense = 2.0 W, Tamb = +25°C
Figure 7. Maximum Output Current as a Function of Vbat
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NCP5007
Output Current Range Set−Up
The current regulation is achieved by means of an external sense resistor connected in series with the LED string.
Vbat
L1
22 mH
FB
1
D1
Load
Vout
4
Q1
CONTROLLER
GND
R1
xW
GND
Figure 8. Output Current Feedback
The current flowing through the LED creates a voltage
drop across the sense resistor R1. The voltage drop is
constantly monitored internally, and maximum peak current
allowed in the inductor is set accordingly in order to keep
constant this voltage drop (and thus the current flowing
through the LED). For example, should one need a 10 mA
output current, the sense resistor should be sized according
to the following equation:
R1 + Feedback Threshold + 200 mV + 20 W
Iout
10 mA
A standard 5% tolerance resistor, 22 W SMD device,
yields 9.09 mA, good enough to fulfill the back light
demand. The typical application schematic diagram is
provided in Figure 9.
Vbat
U1
3
Pulse
EN
Vbat
C1
5
4.7 mF
L1
22 mH
GND
2
1
Vout
GND
MBR0530
NCP5007
D6
22 W
LED
D5
D4
GND
D1
4
FB
R1
(eq. 9)
D3
C2
1.0 mF
D2
GND
GND
LED
LED
LED
Figure 9. Basic Schematic Diagram
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LED
NCP5007
Output Load Drive
The Schottky diode D1, associated with capacitor C2 (see
Figure 9), provides a rectification and filtering function.
When a pulse−operating mode is required:
• A PWM mode control can be used to adjust the output
current range by means of a resistor and a capacitor
connected across FB pin. On the other hand, the
Schottky diode can be removed and replaced by at least
one LED diode, keeping in mind such LED shall
sustain the large pulsed peak current during the
operation.
In order to take advantage of the built−in Boost
capabilities, one shall operate the NCP5007 in the
continuous output current mode. Such a mode is achieved by
using and external reservoir capacitor (see Table 1) across
the LED.
At this point, the peak current flowing into the LED diodes
shall be within the maximum ratings specified for these
devices. Of course, pulsed operation can be achieved, thanks
to the EN signal pin 3, to force high current into the LED
when necessary.
TYPICAL OPERATING CHARACTERISTICS
100
100
4 LED/4 mA
90
80
5 LED/4 mA
EFFICIENCY (%)
EFFICIENCY (%)
80
70
4 LED/10 mA
90
3 LED/4 mA
2 LED/4 mA
60
50
40
30
70
40
30
20
10
3.50
4.00
4.50
5.00
0
2.50
5.50
3.00
3.50
Vbat (V)
80
80
5 LED/15 mA
EFFICIENCY (%)
EFFICIENCY (%)
90
2 LED/15 mA
4 LED/15 mA
50
40
30
70
60
10
4.00
4.50
5.00
4 LED/20 mA
0
2.50
5.50
5 LED/20 mA
2 LED/20 mA
30
20
3.50
3 LED/20 mA
40
10
3.00
5.50
50
20
0
2.50
5.00
100
90
60
4.50
Figure 11. Overall Efficiency vs. Power Supply −
Iout = 10 mA, L = 22 mH
3 LED/15 mA
70
4.00
Vbat (V)
Figure 10. Overall Efficiency vs. Power Supply −
Iout = 4.0 mA, L = 22 mH
100
3 LED/10 mA
50
10
3.00
5 LED/10 mA
60
20
0
2.50
2 LED/10 mA
3.00
3.50
4.00
4.50
5.00
5.50
Vbat (V)
Vbat (V)
Figure 12. Overall Efficiency vs. Power Supply −
Iout = 15 mA, L = 22 mH
Figure 13. Overall Efficiency vs. Power Supply −
Iout = 20 mA, L = 22 mH
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NCP5007
TYPICAL OPERATING CHARACTERISTICS
(All curve conditions: L = 22 mH, Cin = 4.7 mF, Cout = 1.0 mF, Typical curve @ Ta = +25°C)
100
30
2 LED/40 mA
90
25
70
60
5 LED/40 mA
4 LED/40 mA
IOUT = 20 mA Nom
20
IOUT (mA)
EFFICIENCY (%)
80
3 LED/40 mA
50
40
15
10
30
20
IOUT = 10 mA Nom
5
L = 22 mH
TA = 25°C
10
0
2.50
3.00
3.50
4.00
Vbat (V)
4.50
5.00
0
2.5
5.50
3.0
3.5
4.0
4.5
25
25
IOUT = 20 mA Nom
IOUT = 20 mA Nom
20
IOUT (mA)
20
IOUT (mA)
5.5
Figure 15. Current Variation vs. Power Supply with
3 Series LED’s
Figure 14. Overall Efficiency vs. Power Supply −
Iout = 40 mA, L = 22 mH
15
10
15
10
IOUT = 10 mA Nom
IOUT = 10 mA Nom
5
0
2.5
5
L = 22 mH
TA = 25°C
3.0
3.5
4.0
4.5
5.0
0
2.5
5.5
L = 22 mH
TA = 25°C
3.0
3.5
VBAT (V)
204
4
FEEDBACK VARIATION (%)
5
203
Vbat = 3.1 V thru 5.5 V
201
200
199
198
197
196
195
−40
4.5
5.0
5.5
Figure 17. Current Variation vs. Power Supply with
5 Series LED’s
205
202
4.0
VBAT (V)
Figure 16. Current Variation vs. Power Supply with
4 Series LED’s
FEEDBACK VOLTAGE (mV)
5.0
VBAT (V)
3
2
1
Vbat = 3.1V thru 5.5V
0
−1
−2
−3
−4
−20
0
20
40
60
80
−5
−40
100
−20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 18. Feedback Voltage Stability
Figure 19. Feedback Voltage Variation
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10
100
NCP5007
TYPICAL OPERATING CHARACTERISTICS
(All curve conditions: L = 22 mH, Cin = 4.7 mF, Cout = 1.0 mF, Typical curve @ Ta = +25°C)
2.5
1.4
−40°C thru 125°C
1.2
2 LED
2.0
F (mHz)
0.8
0.6
1.5
3 LED
4 LED
1.0
0.4
5 LED
0.5
0.2
0.0
2.7
3.3
3.9
4.5
0
2.5
5.5
5.1
3.0
3.5
4.0
4.5
5.0
Vbat, BATTERY VOLTAGE (V)
Vbat (V)
Figure 20. Standby Current
Figure 21. Typical Operating Frequency
26
OVER VOLTAGE PROTECTION (V)
IStby (μA)
1.0
25
Vbat = 3.6V
Vbat = 2.7V
Vbat = 5.5V
24
23
22
−40 −20
0
20
40
60
80
100
TEMPERATURE(°C)
Figure 22. Overvoltage Protection
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120 130
5.5
NCP5007
TYPICAL OPERATING WAVEFORMS
Vout
Inductor
Current
Conditions: Vbat = 3.6 V, Lout = 22 mH, 5 LED, Iout = 15 mA
Figure 23. Typical Power Up Response
Vout
Inductor
Current
Conditions: Vbat = 3.6 V, Lout = 22 mH, 5 LED, Iout = 15 mA
Figure 24. Typical Startup Inductor Current and Output Voltage
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NCP5007
TYPICAL OPERATING WAVEFORMS
Inductor
Current
Conditions: Vbat = 3.6 V, Lout = 22 mH, 5 LED, Iout = 15 mA
Figure 25. Typical Inductor Current
Vout Ripple
50 mV/div
Inductor
Current
Conditions: Vbat = 3.6 V, Lout = 22 mH, 5 LED, Iout = 15 mA
Figure 26. Typical Output Voltage Ripple
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NCP5007
TYPICAL OPERATING WAVEFORMS
Output Voltage
Inductor Current
Test Conditions: L = 22 mH, Iout = 15 mA, Vbat = 3.6 V, Ambient Temperature, LED = 5
Figure 27. Typical Output Peak Voltage
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NCP5007
TYPICAL APPLICATIONS CIRCUITS
Standard Feedback
The standard feedback provides constant current to the
LEDs, independently of the Vbat supply and number of
LEDs in series. Figure 28 depicts a typical application to
supply 13 mA to the load.
Vbat
Vbat
U1
3
C1
EN
Vbat
5
4.7 mF
L1
22 mH
GND
2
1
GND
GND
D1
Vout 4
FB
MBR0530
NCP5007
C2
1.0 mF
R1
D6
D5
D4
D3
D2
15 W
LED
LED
LED
LED
LED
GND
GND
Figure 28. Basic DC Current Mode Operation with
Analog Feedback
PWM Operation
Although the pulsed mode will provide a good dimming
function, it will yield high switching transients which are
difficult to filter out in the control loop. As such this first
approach is not recommended. The output current depends
upon the duty cycle of the signal presented to the node pin 1:
this is very similar to the digital control shown in Figure 30.
The average mode yields a noise−free operation since the
converter operates continuously, together with a very good
dimming function. The cost is an extra resistor and one extra
capacitor, both being low cost parts.
The analog feedback pin 1 provides a way to dim the LED
by means of an external PWM signal as depicted in
Figure 29. Taking advantage of the high internal impedance
presented by the FB pin, one can set up a simple R/C network
to accommodate such a dimming function. Two modes of
operation can be considered:
• Pulsed mode, with no filtering
• Averaged mode with filtering capacitor
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NCP5007
Vbat
Vbat
U1
3
C1
EN
5
Vbat
4.7 mF
L1
22 mH
Average Network
2
GND
R2
R3
150 k
10 k
1
PWM
GND
D1
Vout 4
FB
MBR0530
NCP5007
C3
100 nF
GND
C2
1.0 mF
R4
5.6 k
GND
GND
R1
D6
D5
D4
D3
D2
10 W
LED
LED
LED
LED
LED
GND
Sense Resistor
NOTE: RC filter R2 and C3 is optional (see text)
Figure 29. Basic DC Current Mode Operation with PWM Control
To implement such a function, lets consider the feedback
input as an operational amplifier with a high impedance input
(reference schematic Figure 29). The analog loop will keep
going to balance the current flowing through the sense
resistor R1 until the feedback voltage is 200 mV. An extra
resistor (R4) isolates the FB node from low resistance to
ground, making possible to add an external voltage to this pin.
The time constant R2/C3 generates the voltage across C3,
added to the node pin 1, while R2/R3/R4/R1/C3 create the
discharge time constant. In order to minimize the pick up
noise at FB node, the resistors shall have relative medium
value, preferably well below 1.0 MW. Consequently, let
R2 = 150 k, R3 = 10 k and R4 = 5.6 k. In addition, the
feedback delay to control the luminosity of the LED shall be
acceptable by the user, 10 ms or less being a good
compromise. The time constant can now be calculated based
on a 400 mV offset voltage at the C3/R2/R3 node to force
zero current to the LED. Assuming the PWM signal comes
from a standard gate powered by a 3.0 V supply, running at
5.0 kHz, then full dimming of the LED can be achieved with
a 95% span of the Duty Cycle signal.
Digital Control
An alternative method of controlling the luminosity of the
LEDs is to apply a PWM signal to the EN pin (see
Figure 30). The output current depends upon the Duty
Cycle, but care must be observed as the DC−DC converter
is continuously pulsed ON/OFF and noise is likely to be
generated.
Vbat
U1
3
Pulse
EN
Vbat
C1
5
4.7 mF
L1
22 mH
GND
2
1
GND
GND
D1
Vout 4
FB
MBR0530
NCP5007
R1
GND
D6
C2
1.0 mF
D5
D4
D3
D2
GND
5.6 W
NOTE: Pulse width and frequency depends upon the application constraints.
Figure 30. Typical Semi−Pulsed Mode of Operation
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NCP5007
Typical LEDs Load Mapping
Since the output power is battery limited (see Figure 5),
one can arrange the LEDs in a variety of different
configurations. Powering ten LEDs can be achieved by a
series/parallel combination as depicted in Figure 31.
50 mA
75 mA
D1
LED
D5
LED
D2
LED
D6
LED
D3
LED
D7
LED
D4
LED
D8
LED
7.0 V (Typ.)
Load
14 V (Typ.)
Load
D1
LED
D3
LED
D5
LED
D7
LED
D9
LED
D2
LED
D4
LED
D6
LED
D8
LED
D10
LED
Sense
Resistor
R1
2.7 W
GND
60 mA
R1
3.9 W
Load
10.5 V (Typ.)
Sense
Resistor
GND
Test conditions: Vbat = 3.6 V
Lout = 22 mH
Cout = 1.0 mF
D1
LED
D4
LED
D7
LED
D10
LED
D13
LED
D2
LED
D5
LED
D8
LED
D11
LED
D14
LED
D3
LED
D6
LED
D9
LED
D12
LED
D15
LED
Sense
Resistor
R1
3.3 W
GND
Figure 31. Examples of Possible LED Arrangements
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17
NCP5007
ON Semiconductor provides a demo board to evaluate the performance of the NCP5007. The schematic for that demo board
is illustrated in Figure 32.
TP3
Vbat
Vbat
C1
Vbat
4.7 mF/10 V
S2
3
2
1
SELECT
GND
GND
S1
3
3
2
1
MANUAL
EN
R3
Vbat
5
10 k
2
GND
S3
D1
Vout
3
2
1
R2
10 k
TP1
Vout
L1
22 mH
GND
BRIGHTNESS
JP1
ISense
U1
R5
1
4
MBR0530
FB
C3
0R
NCP5007
MODULATION
J3
GND
Jumper = 0 W
R1
TP2
FB
150 k
GND
J2 Vbat
2
1
Z1
GND
PWR
J1
1
2
R4
5.6 k
C2
100 nF
Vbat
R10
D6
D5
D4
D3
D2
10 R
LED
LED
LED
LED
LED
GND
Figure 32. NCP5007 Demo Board Schematic Diagram
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18
NCP5007
Table 1. Recommended External Parts
Part
Manufacturer
Description
Part Number
30 V Low Vf Schottky Diode
ON Semiconductor
SOD−123 (1.6 x 3.2 mm)
MBR0530T1
20 V Low Vf Schottky Diode
ON Semiconductor
SOD−323 (1.25 x 2.5 mm)
NSR0320MW2T1
20 V Low Vf Schottky Diode
ON Semiconductor
SOD−563 (1.6 x 1.6 mm)
NSR0320XV6T1
Ceramic Cap. 1.0 mF/16 V
MURATA
GRM42−X7R
GRM42−6X7R−105K16
Ceramic Cap. 4.7 mF/6.3 V
MURATA
GRM40−X5R
GRM40−X5R−475K6.3
Inductor 22 mH
CoilCraft
1008PS−Shielded
1008PS−223MC
Inductor 22 mH
CoilCraft
Power Wafer
LPQ4812−223KXC
Figure 33. NCP5007 Demo Board PCB: Top Layer
Figure 34. NCP5007 Demo Board Top Silkscreen
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NCP5007
FIGURES INDEX
Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Figure 7:
Figure 8:
Figure 9:
Figure 10:
Figure 11:
Figure 12:
Figure 13:
Figure 14:
Figure 15:
Figure 16:
Figure 17:
Figure 18:
Figure 19:
Figure 23:
Figure 24:
Figure 25:
Figure 26:
Figure 27:
Figure 28:
Figure 29:
Figure 30:
Figure 31:
Figure 32:
Figure 33:
Figure 34:
Typical Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Basic DC−DC Converter Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Basic DC−DC Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Maximum Output Power as a Function of the Battery Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical Inductor Peak Current as a Function of Vbat Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Maximum Output Current as a Function of Vbat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Output Current Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Basic Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Overall Efficiency vs. Power Supply − Iout = 4.0 mA, L = 22 mH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overall Efficiency vs. Power Supply − Iout = 10 mA, L = 22 mH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overall Efficiency vs. Power Supply − Iout = 15 mA, L = 22 mH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overall Efficiency vs. Power Supply − Iout = 20 mA, L = 22 mH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overall Efficiency vs. Power Supply − Iout = 40 mA, L = 22 mH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Feedback Voltage Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Feedback Voltage Variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Standby Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Typical Operating Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Overvoltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Typical Power Up Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Typical Startup Inductor Current and Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Typical Inductor Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Typical Output Voltage Ripple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Typical Output Peak Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Basic DC Current Mode Operation with Analog Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Basic DC Current Mode Operation with PWM Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Typical Semi−Pulsed Mode of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Examples of Possible LED Arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
NCP5007 Demo Board Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
NCP5007 Demo Board PCB: Top Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
NCP5007 Demo Board Top Silkscreen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
NOTE CAPTIONS INDEX
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
This device series contains ESD protection and exceeds the following tests . . . . . . . . . . . . . . . . . . . . . . . . . .
The maximum package power dissipation limit must not be exceeded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Latchup current maximum rating: "100 mA per JEDEC standard: JESD78 . . . . . . . . . . . . . . . . . . . . . . . . .
Moisture Sensivity Level (MSL): 1 per IPC/JEDEC standard: J−STD−020A . . . . . . . . . . . . . . . . . . . . . . . . .
The overall tolerance depends upon the accuracy of the external resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ABBREVIATIONS
EN
FB
POR
Enable
Feed Back
Power On Reset: Internal pulse to reset the chip when the power supply is applied
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20
4
4
4
4
5
NCP5007
PACKAGE DIMENSIONS
TSOP−5
SN SUFFIX
CASE 483−02
ISSUE C
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. MAXIMUM LEAD THICKNESS INCLUDES
LEAD FINISH THICKNESS. MINIMUM LEAD
THICKNESS IS THE MINIMUM THICKNESS
OF BASE MATERIAL.
4. A AND B DIMENSIONS DO NOT INCLUDE
MOLD FLASH, PROTRUSIONS, OR GATE
BURRS.
D
S
5
4
1
2
3
B
L
MILLIMETERS
INCHES
DIM MIN
MAX
MIN
MAX
A
2.90
3.10 0.1142 0.1220
B
1.30
1.70 0.0512 0.0669
C
0.90
1.10 0.0354 0.0433
D
0.25
0.50 0.0098 0.0197
G
0.85
1.05 0.0335 0.0413
H 0.013 0.100 0.0005 0.0040
J
0.10
0.26 0.0040 0.0102
K
0.20
0.60 0.0079 0.0236
L
1.25
1.55 0.0493 0.0610
M
0_
10 _
0_
10 _
S
2.50
3.00 0.0985 0.1181
G
A
J
C
0.05 (0.002)
H
M
K
SOLDERING FOOTPRINT*
0.95
0.037
1.9
0.074
2.4
0.094
1.0
0.039
0.7
0.028
SCALE 10:1
mm Ǔ
ǒinches
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
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For additional information, please contact your
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NCP5007/D