NCV78702
Multiphase Booster LED
Driver for Automotive Front
Lighting
The NCV78702 is a single−chip and high efficient booster for smart
Power ballast and LED Driver designed for automotive front lighting
applications like high beam, low beam, DRL (daytime running light),
turn indicator, fog light, static cornering, etc. The NCV78702 is in
particular designed for high current LEDs and with NCV78723 (dual
channel buck)/713 (single channel) provides a complete solution to
drive multiple LED strings of up−to 60 V. It includes a current−mode
voltage boost controller which also acts as an input filter with a
minimum of external components. The available output voltage can be
customized. Two devices NCV78702 can be combined and the booster
circuits can operate together to function as a multiphase booster
(2−phase, 3−phase, 4−phase) in order to further optimize the filtering
effect of the booster and lower the total application BOM cost for
higher power. Thanks to the SPI programmability, one single
hardware configuration can support various application platforms.
Features
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1 24
QFN24
MW SUFFIX
CASE 485L
MARKING DIAGRAM
N702−0
ALYWG
G
N702
A
L
Y
W
G
= Specific Device Code
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
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Single Chip
Multiphase Booster
High Overall Efficiency
Minimum of External Components
Active Input Filter with Low Current Ripple from Battery
Integrated Boost Controller
Programmable Input Current Limitation
High Operating Frequencies to Reduce Inductor Sizes
PCB Trace for Current Sense Shunt Resistor is Possible
Low EMC Emission
SPI Interface for Dynamic Control of System Parameters
Fail Save Operating (FSO) Mode, Stand−Alone Mode
Integrated Failure Diagnostic
(Note: Microdot may be in either location)
ORDERING INFORMATION
See detailed ordering and shipping information on page 31 of
this data sheet.
Typical Applications
High Beam
Low Beam
DRL
Position or Park Light
Turn Indicator
Fog
Static Cornering
©
Semiconductor Components Industries, LLC, 2016
1
January, 2016 − Rev. 1
Publication Order Number:
NCV78702/D
NCV78702
TYPICAL APPLICATION SCHEMATIC
V_Batt
(after rev . pol. prot.)
C_BST _IN
D1
L1
C_BC2
VBOOSTDIV
VGATE 1
IBSTSENSE 1+
R_BC1
COMP
IBSTSENSE 1−
R_SENSE 1
RD2
RD1
T1
C_BST
Vboost
C_BC1
C_BB
VCC of MCU
C_VDRIVE
VDRIVE
R_SDO
C_DD
VDD
VBB
ON Semiconductor
LED driver
2 phase booster
NCV 78702
Phase 1
L2
D2
VGATE 2
T2
IBSTSENSE 2+
R_SENSE 2
IBSTSENSE 2−
ENABLE 1
mC
Phase 2
BSTSYNC /TST /TST 1
FSO / ENABLE2
SPI _SCLK /TST 2
SPI _SDI
SPI _SDO
SPI _SCS
GND
GNDP
PWR GND
Sig GND
Figure 1. Typical Application Schematic
Table 1. EXTERNAL COMPONENTS
Component
L1, L2
T1, T2
D1, D2
R_SENSE1, R_SENSE2
C_BST
C_BB
C_VDRIVE
C_VDRIVE_ESR
C_DD
C_DD_ESR
R_SDO
C_BC1
C_BC2
R_BC1
RD1
RD2
Function
Booster regulator coil
Booster regulator switching transistor
Booster regulator diode
Booster regulator current sensing resistor
Booster regulator output capacitor
V
BB
decoupling capacitance (Note 1)
Capacitor for V
DRIVE
regulator
ESR of V
DRIVE
capacitor
V
DD
decoupling capacitor
ESR of V
DD
capacitor
SPI pull−up resistor
Booster compensation network
Booster compensation network
Booster compensation network
Booster output voltage feedback divider (Note 2)
Booster output voltage feedback divider (Note 2)
Typ. Value
10
e.g. NTD6416ANL
e.g. MBR5H100MFS
10
0.44
1
1
max. 200
1
max. 200
1
See Booster Compensator Model section
See Booster Compensator Model section
See Booster Compensator Model section
107 (±1% tolerance)
3.24 (±1% tolerance)
kW
kW
mW
mF/W
mF
mF
mW
mF
mW
kW
Unit
mH
1. The value represents a potential initial startup value on a generic application. The actual size of the boost capacitor depends on the
application defined requirements (such as power level, operating ranges, number of phases) and transient performances with respect to the
rest of BOM. Please refer to application notes and tools provided by ON Semiconductor for further guidance. The chosen value must be
validated in the application.
2. Proposed values. Divider ratio (BSTDIV_RATIO) has to be 34. Tolerance of the resistors has to be
±1%
to guarantee Booster parameters
(see Table 12).
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2
NCV78702
VBB
VDRIVE
LDR
Booster
DIV
Error
amplifier
Vref
VBOOSTDIV
COMP
VDD
LDR
Vdrive
Bandgap
VGATE 1
Vref
POR
PWM
Predriver
IBSTSENSE 1+
Digital control
Bias
Current
sense CMP
Vdrive
IBSTSENSE 1−
TSD
VGATE 2
OSC
PWM
Predriver
IBSTSENSE 2+
OTP
BSTSYNC ,
ENABLE 1,2,
TST 1/TST 2
SPI
Current
sense CMP
IBSTSENSE 2−
5V tolerant input
5V tolerant input
OD output
/
GND
GNDP
Figure 2. Block Diagram
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NCV78702
PACKAGE AND PIN DESCRIPTION
24
VBB
23
VDRIVE
22
VDD
21
GND
20
COMP
19
VBOOSTDIV
1
NC
ENABLE 1
18
2
VGATE 1
BSTSYNC /
TST/TST1
17
3
VGATE 2
SDO
16
NCV78702
4
NC
SDI
15
5
NC
CSB/SCS
14
IBST
SENSE 1 −
IBST
SENSE 2 −
IBST
SENSE 1 +
IBST
SENSE 2 +
GNDP
7
8
9
10
11
Figure 3. Pin Connections – QFN24 4x4 0.5
Table 2. PIN DESCRIPTION
Pin No. QFN24 4x4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Pin Name
NC
VGATE1
VGATE2
NC
NC
NC
GNDP
IBSTSENSE1+
IBSTSENSE1−
IBSTSENSE2+
IBSTSENSE2−
FSO/ENABLE2
SCLK/TST2
CSB/SCS
SDI
SDO
BSTSYNC/TST/TST1
ENABLE1
VBOOSTDIV
COMP
GND
VDD
VDRIVE
VBB
NC
Booster MOSFET gate pre−driver
Booster MOSFET gate pre−driver
NC
NC
NC
Power ground
Coil1 current positive feedback input
Coil1 current negative feedback input
Coil2 current positive feedback input
Coil2 current negative feedback input
FSO/ENABLE2 input
SPI clock / TST2 IO
SPI chip select (chip select bar)
SPI data input
SPI data output – pull up
External clock for the boost regulator/ TM entry/ TST1 IO
ENABLE1 input
Booster high voltage feedback input
Compensation for the Boost regulator
Ground
3 V logic supply
10 V supply
Battery supply
Description
I/O Type
NC
MV out
MV out
NC
NC
NC
Ground
MV in
MV in
MV in
MV in
MV in
MV in
MV in
MV in
MV open−drain
HV in
MV in
HV in
LV in/out
Ground
LV supply
MV supply
HV supply
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4
FSO/
ENABLE 2
6
NC
SCLK/
TST2
13
12
NCV78702
Table 3. ABSOLUTE MAXIMUM RATINGS
Characteristic
Battery supply voltage (Note 4)
Logic supply voltage (Note 5)
Gate driver supply voltage (Note 6)
Input current sense voltage (Note 7)
Medium voltage IO pins (Note 8)
Storage Temperature (Note 9)
Electrostatic Discharge on Component Level (Note 10)
Human Body Model
Charge Device Model
Symbol
V
BB
V
DD
V
DRIVE
IBSTSENSEPx,
IBSTSENSENx
IOMV
T
STRG
V
ESD_HBM
V
ESD_CDM
Min
−0.3
−0.3
−0.3
−1.0
−0.3
−50
−2
−500
Max
36 (Note 3)
3.6
12
12
6.5
150
+2
+500
Unit
V
V
V
V
V
°C
kV
V
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
3. Absolute maximum rating for VBB is 40 V for limited time < 0.5 s
4. Absolute maximum rating for pins: VBB, BSTSYNC/TST/TST1, VBOOSTDIV
5. Absolute maximum rating for pins: VDD, COMP
6. Absolute maximum rating for pins: VDRIVE, VGATE1, VGATE2
7. Absolute maximum rating for pins: IBSTSENSE1+, IBSTSENSE1−, IBSTSENSE2+, IBSTSENSE2−
8. Absolute maximum rating for pins: SCLK/TST2, CSB, SDI, SDO, ENABLE1, FSO/ENABLE2
9. For limited time up to 100 hours. Otherwise the max storage temperature is 85°C.
10. This device series incorporates ESD protection and is tested by the following methods:
ESD Human Body Model tested per EIA/JESD22−A114
ESD Charge Device Model tested per ESD−STM5.3.1−1999
Latch−up Current Maximum Rating:
v100
mA per JEDEC standard: JESD78
Operating ranges define the limits for functional
operation and parametric characteristics of the device. A
mission profile (Note 11) is a substantial part of the
Table 4. RECOMMENDED OPERATING RANGES
Characteristic
Battery supply voltage (Note 12 and 13)
Logic supply voltage (Note 14)
VDD current load
Medium voltage IO pins
Input current sense voltage
Functional operating junction temperature range (Note 15)
Parametric operating junction temperature range (Note 16)
operation conditions; hence the Customer must contact
ON Semiconductor in order to mutually agree in writing on
the allowed missions profile(s) in the application.
Symbol
V
BB
V
DD
I
DD
IOMV
IBSTSENSEPx,
IBSTSENSENx
T
JF
T
JP
Min
5
3.1
Typ
Max
30
3.5
50
Unit
V
V
mA
V
V
°C
°C
0
−0.1
−45
−40
5
1
155
150
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond
the Recommended Operating Ranges limits may affect device reliability.
11. A mission profile describes the application specific conditions such as, but not limited to, the cumulative operating conditions over life time,
the system power dissipation, the system’s environmental conditions, the thermal design of the customer’s system, the modes, in which the
device is operated by the customer, etc. No more than 100 cumulated hours in life time above T
tw
.
12. Minimum V
BB
for OTP memory programming is 15.8 V.
13. VDRIVE is supplied from VBB, it must be verified that VDRIVE voltage is appropriate for the external FETs.
14. VBB > 5 V
15. The circuit functionality is not guaranteed outside the functional operating junction temperature range. Also please note that the device is
verified on bench for operation up to 170°C but that the production test guarantees 155°C only.
16. The parametric characteristics of the circuit are not guaranteed outside the Parametric operating junction temperature range.
Table 5. THERMAL RESISTANCE
Characteristic
Thermal Resistance Junction to Exposed Pad (Note 17)
Package
QFN24 4x4
Symbol
Rthjp
Min
Typ
2.82
Max
Unit
°C/W
17. Includes also typical solder thickness under the Exposed Pad (EP). Thermal resistance junction to PCB Top Layer.
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