Datasheet
LED Drivers for LCD Backlights
White LED Driver for large LCD
Panels (DCDC Converter type)
BD93942F
Features
4ch LED constant current driver and DC/DC converter
Maximum LED Current: 150mA
LED Feedback Voltage: 0.45V (@ILED=150mA)
so lower heat. Adjustable Feed Back Voltage
by following LED Current setting.
2% LED current accuracy (ADIM=2.5V,
when each LED is set to 100mA)
Analog current (Linear) dimming at ADIM pin
LED pin rating 60V
Individual detection and individual LED OFF for both
open and short circuits
Built-in ISET pin short-circuit protection circuit
FET’s Gate (N pin) is driven by 5.8V swing
Built-in Vout discharge circuit for shutdown
Built-in Vout overvoltage protection (OVP) /
reduced voltage protection (SCP) circuit
SOP16 package
General Description
BD93942F is a high efficiency driver for white LEDs and
designed for large LCDs. These ICs are built-in a boost
DCDC converters that employ an array of LEDs as the
light source. BD93942F have some protect function
against fault conditions, such as the over-voltage
protection (OVP), the over current limit protection of
DCDC (OCP), the short circuit protection (SCP), the
open detection of LED string. Therefore BD93942F are
available for the fail-safe design over a wide range
output voltage.
Key Specification
Operating power supply voltage range: 9.0V to 35.0V
LED minimum current
30mA
LED maximum current:
150mA
Oscillator frequency:
150kHz (RT=100kΩ)
Operating Current:
3.7mA (Typ.)
Operating temperature range:
-40°C to +85°C
Applications
TV, Computer Display, Notebook, LCD Backlighting
Package
SOP16
W(Typ.) x D(Typ.) x H(Max.)
10.00mm x 6.20mm x 1.71mm
Figure 1. SOP16
Typical Application Circuit
VIN
Inductor
VIN
Diode
Connector
CIN
COUT
REG58
CREG
RN2
FET
DN RN1
RCS
REG58
STB
N
VCC
RRT
AGND
ROVP1
ROVP2
COVP
RFB CFB1
RISET
ADIM
RVCC
CVCC
GND
PGND
ON/OFF
CS
LED4
RT
LED3
CLED4
CLED3
OVP
SSFB
LED2
ISET
LED1
ADIM
PWM
CLED2
CLED1
PWM
Figure 2. Typical Application Circuit
○Product structure：Silicon monolithic integrated circuit
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Datasheet
BD93942F
Absolute maximum ratings (Ta=25°C)
Parameter
Symbol
Ratings
Unit
VCC
36
V
STB, ADIM, OVP, PWM
36
V
Power supply voltage
STB, ADIM, OVP, PWM terminal voltage
LED1 to 4 terminal voltage
REG58, CS, N, ISET, SSFB, RT terminal voltage
LED1 to 4
60
V
REG58, CS, N,
ISET, SSFB, RT
7
V
Pd
0.62 *1
W
Power dissipation (SOP16)
Operating temperature range
Topr
-40 to +85
°C
Storage temperature range
Tstg
-55 to +150
°C
Tjmax
150
°C
Junction temperature
*1 Ta = 25°C or more, diminished at -5mW/°C in the case of SOP16
(when 1-layer / 70.0 mm x 70.0 mm x 1.6 mm board is mounted)
Operating Ratings
Parameter
VCC supply voltage
Symbol
Limits
Unit
VCC
9.0 to 35.0
V
Min. output current of LED1 to 4
ILED_MIN
30
Max. output current of LED1 to 4
ILED_MAX
150
mA *1
mA
*1,2
ADIM input voltage1 (use ADIM function)
VADIM1
ADIM input voltage1 (don’t use ADIM function)
VADIM2
0.2 to 2.7 (normal op.)
1.0 to 2.7
(start up)
REG58 to 35.0
Fsw
100 to 800
DC/DC oscillation frequency
V *3
V
kHz
Min. on-duty time for PWM light modulation
PWM_MIN
30
μs
*1 The amount of current per channel.
*2 If LED makes significant variations in its reference voltage, the driver will increase power dissipation, resulting in a rise
in package temperature.
To avoid this problem, design the board with thorough consideration given to heat radiation measures.
*3 To avoid unused LED pin’s misdetection, set ADIM within 1.0V to 2.7V at start up stage. After unused LED pin’s
detection, set ADIM within 0.2V to 2.7V in normal operation.
Pin Configuration
1
REG58
VCC
16
2
CS
ADIM
15
3
N
RT
14
4
GND
SSFB
13
5
OVP
ISET
12
6
STB
PWM
11
7
LED1
LED4
10
8
LED2
LED3
9
SOP16
Figure 3. Pin Configuration
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Datasheet
BD93942F
Marking diagram and physical dimension
SOP16
BD93942F
LOT No.
Figure 4. Physical Dimension
Electrical Characteristics (Unless otherwise noted, Ta = 25oC, VCC=24V)
Parameter
Symbol
Limit
Min.
Typ.
Max.
Unit
Condition
[Whole Device]
Circuit current while in operation
ICC
-
3.7
7.4
mA
STB=3V,PWM=3V,
RT=100kΩ
Circuit current while in standby
ISTB
-
40
80
μA
STB=0V
REG58 Output Voltage
REG58
5.742
5.8
5.858
V
IO=0mA
REG58 available current
IREG58
15
-
-
mA
UVLO release voltage
VUVLO_VCC
6.5
7.5
8.5
V
UVLO hysteresis voltage
VUHYS_VCC
150
300
600
mV
VLED
0.425
0.450
0.475
V
fsw
142.5
150.0
157.5
kHz
RT=100kΩ
Max. duty cycle per output of N pin
DMAX
83
90
97
%
RT=100kΩ
On resistance on N pin source side
RONH
-
4
8
Ω
ION=-10mA
On resistance on N pin sink side
RONL
-
3
6
Ω
ION=10mA
SSFB pin source current
(at soft start)
ISSSO
-13.0
-10.0
-7.0
uA
SSFB=2V
SSFB sink current
IFBSI
50
100
150
μA
LED=2.0V,SSFB=1.0V
SSFB source current
IFBSO
-150
-100
-50
μA
LED=0V, SSFB=1.0V
VCS
0.40
0.45
0.50
V
CS=SWEEP UP
[REG58 Block]
[UVLO Block]
VCC=SWEEP UP
VCC=SWEEP DOWN
[DC/DC Block]
Error amp. Reference voltage
Oscillation frequency
Over current detection voltage
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ISET=50kΩ, ADIM=2.5V
ILED=150mA
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Datasheet
BD93942F
Electrical Characteristics (Unless otherwise noted, Ta = 25oC, VCC=24V)
Parameter
Symbol
Limit
Unit
Condition
Min.
Typ.
Max.
VOVP
2.7
3.0
3.3
V
VOVP_HYS
50
100
200
mV
OVP=SWEEP DOWN
VSCP
0.04
0.10
0.25
V
OVP=SWEEP DOWN
LED pin current accuracy 1
dILED1
-2
-
2
%
LED pin current accuracy 2
dILED2
-3.2
-
3.2
%
LED pin current accuracy 3
dILED3
-4.6
-
4.6
%
LED pin current accuracy 4
dILED4
-8
-
8
%
LED pin current accuracy 5
dILED5
-3
-
3
%
LED pin Leakage Current
ILLED
-2.5
-
2.5
μA
LED=60V
LED open detection voltage
VOPEN
0.05
0.2
0.285
V
LED=SWEEP DOWN
LED short detection voltage
VSHORT
4
5
6
V
LED=SWEEP UP
ILADIM
-2.5
-
2.5
μA
ADIM=3V
STB pin high-level voltage
STBH
2
-
35
V
STB=SWEEP UP
STB pin low-level voltage
STBL
-0.3
-
0.8
V
STB=SWEEP DOWN
STB pin pull-down resistance
RSTB
500
1000
1500
kΩ
STB=3.0V
PWM pin high-level voltage
PWMH
2
-
35
V
PWM=SWEEP UP
PWM pin low-level voltage
PWML
-0.3
-
0.8
V
PWM= SWEEP DOWN
PWM pin pull-down resistance
RPWM
180
300
420
kΩ
PWM=3.0V
-
0.655
-
sec
RT=75kΩ
ms
RT=75kΩ
[DC/DC Protection Block]
Overvoltage protection detection
voltage
Overvoltage protection detection
hysteresis voltage
Short circuit protection detection
voltage
OVP=SWEEP UP
[LED Driver Block]
ADIM pin Input Current
ILED=100mA,
(ADIM=2.5V,ISET=75kΩ)
ILED=70mA,
(ADIM=1.75V,ISET=75kΩ)
ILED=50mA,
(ADIM=1.25V,ISET=75kΩ)
ILED=30mA,
(ADIM=0.75V,ISET=75kΩ)
ILED=100mA,
(ADIM=7V,ISET=75kΩ)
[STB Block]
[PWM Block]
[Failure Indication Block (Open Drain)]
AUTO Timer
Abnormal Detection Timer
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BD93942F
Pin Descriptions (SOP16)
Pin No
Pin Name
In/Out
Function
Rating [V]
1
REG58
Out
2
CS
In
3
N
Out
4
GND
-
Ground pin
5
OVP
In
Overvoltage protection detection pin
-0.3 to 36
6
STB
In
Enable pin
-0.3 to 36
7
LED1
Out
Output pin 1 for LED
-0.3 to 60
8
LED2
Out
Output pin 2 for LED
-0.3 to 60
9
LED3
Out
Output pin 3 for LED
-0.3 to 60
10
LED4
Out
Output pin 4 for LED
-0.3 to 60
External PWM light modulation signal input pin for LED1-4
-0.3 to 36
LED current setting resistor connection pin
-0.3 to 7
Soft start setting, Loop compensation setting pin
-0.3 to 7
Power supply for N pin
-0.3 to 7
DC/DC output current detection and OCP detection pin
-0.3 to 7
DC/DC switching output pin
-0.3 to 7
-
11
PWM
In
12
ISET
Out
13
SSFB
In/Out
14
RT
Out
DC/DC drive frequency setting resistor connection pin.
-0.3 to 7
15
ADIM
In
Analog dimming DC voltage input pin
-0.3 to 36
16
VCC
In
Power supply pin
-0.3 to 36
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BD93942F
Pin ESD Type
REG58 / N /GND/ CS
ADIM
SSFB
SSFB
ADIM
LED1~4
RT
STB
STB
RT
PWM
ISET
OVP
ISET
Figure 5. Pin ESD Type
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Datasheet
BD93942F
Block Diagram
Figure 6. Block Diagram
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BD93942F
Typical Performance Curve
1000
8
VCC=24V
Ta=25°C
STB=3V,
PWM=3V,
RT=100kΩ
7
N Frequency [MHz]
6
Icc [mA]
5
4
3
100
2
1
10
0
8
12
16
20
24
VCC [V]
28
32
10
36
1 40
200
160
VCC=24V
Ta=25°C
RISET=75kΩ
ADIM=2.5V
VCC=24V
Ta=25°C
RISET=75kΩ
1 20
1 00
120
ILED [mA]
ILE D [mA]
140
1000
Figure 8. N Frequency [MHz] vs. R_RT [kΩ]
Figure 7. Operating Current (ICC) [mA] vs. VCC[V]
180
100
R_RT [kΩ]
100
80
60
80
60
40
40
20
20
0
0
-40 -20
0
20
40 60 80 100 120 140
Temp [℃]
0
Figure 9. LED Current (ILED) [mA] vs. Temp [oC]
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1
1.5
2
ADIM [V]
2.5
3
3.5
Figure 10. LED Current (ILED) [mA] vs. ADIM[V],
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Datasheet
BD93942F
Pin Function
○REG58 (1pin)
The REG58 pin is used in the DC/DC converter driver block to output 5.8V power. The maximum operating current is 15mA.
Using the REG58 pin at a current higher than 15mA can affect the N pin output pulse, causing the IC to malfunction and
leading to heat generation of the IC itself. To avoid this problem, it is recommended to make load setting to the minimum
level.
Please place the ceramic capacitor connected to REG58 pin (2.2μF to 10μF) closest to REG58-GND pin.
○CS (2pin)
The CS pin has the following two functions:
1. DC/DC current mode current feedback function
Current flowing through the inductor is converted into voltage by the current sensing resistor RCS connected to the CS pin
and this voltage is compared with voltage set with the error amplifier to control the DC/DC output voltage.
2. Inductor current limit function
The CS pin also incorporates the over current protection (OCP) function. If the CS pin voltage reaches 0.45V (Typ.) or more,
switching operation will be forcedly stopped.
○N (3pin)
The N pin is used to output power to the external NMOS gate driver for the DC/DC converter in the amplitude range of
approx. 0 to REG58. ON resistances is 4.0Ω(typ.) in sorrce (H side), 3.0Ω(typ.) in sink (L side).
Frequency setting can be made with a resistor connected to the RT pin. For details of frequency setting, refer to the
description of the RT pin.
○GND (4pin)
Ground of the IC.
○OVP (5pin)
The OVP pin is an input pin for over-voltage protection and short circuit protection of DC/DC output voltage. If over-voltage
is detected, the OVP pin will stop the DC/DC converter conducting step-up operation. When the short circuit protection
(SCP) function is activated, the DC/DC converter will stop operation, and then the timer will start counting. When the timer
completes counting the preset period of time, the LED drivers are stopped.
The OVP pin is of the high impedance type and involves no pull-down resistor, resulting in unstable potential in the
open-circuited state. To avoid this problem, be sure to make input voltage setting with the use of a resistive divider or
otherwise.
○STB (6pin)
The STB pin is used to make setting of turning ON and OFF the IC and allowed for use to reset the IC from shutdown.
Note: The IC state is switched (i.e., the IC is switched between ON and OFF state) according to voltages input in the STB
pin. Avoid using the STB pin between two states (0.8 to 2.0V).
When STB signal is set to Low or High, change it from Low to High after REG58 output completely discharges.
○LED1 – LED4 (7pin – 10pin)
The LED1 to 4 pins are used to output constant current to LED drivers. Current value setting can be made by connecting a
resistor to the ISET pin.
For the current value setting procedure, refer to the description of “ISET pin”.
If any of the LED pins is put in an erroneous state (e.g. short circuit mode, open circuit mode, or ground short circuit mode),
the relevant protection function will be activated.
This IC is detected automatically that it is an unused channel by asssuming the LED terminal to be connected to GND
before start up.
○PWM (11pin)
The PWM pin is used to turn ON and OFF LED drivers. Light can be modulated by changing the duty cycle through the
direct input of a PWM light modulation signal. The high and low voltage levels of PWM pin is as listed in the table below:
State
PWM Voltage
LED ON state
PWM= 2.0V to 35V
LED OFF state
PWM= -0.3V to 0.8V
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BD93942F
○ISET (12pin)
The ISET pin is an output current setting resistor. Output current ILED varies in inverse proportion to resistance.
The relation between output current ILED and the resistance of ISET pin connection resistor RISET is given by the following
equation:
I LED [ mA]
3000
V ADIM [V ]
R ISET [ kΩ]
I LED [mA]
7500
RISET [ kΩ]
(ADIM=0.2V to2.7V)
(ADIM>4V to 35V)
Output current setting should be made in the range of 30mA to 150mA.
It prepares automatically to suitable LED feedback voltage that can output LED current set by ISET pin.
In short LED feedback voltage is dropped when the LED current is small and the IC heating is held automatically.
In case of a large current is needed, raise the LED pin feedback voltage. And it adjusts automatically to LED pin voltage
that can be flow large LED current.
The calculation is as below.
VLED 3 I LED [ A] [V ]
( ILED 117 mA)
VLED 0.35[V ](
typ ) ( ILED 117 mA)
The LED feedback voltage (VLED) is clamped to 0.35V (typ.) when the LED current (ILED) is less than 117mA.
ADIM input range is from 0V to 35V. And the range which the LED currents change with linearity is from 0.2V to 2.7V.
When it reaches under VISET×0.90V(typ.), the LED current is off to prevent from passing a large current to the LED pin
when the RISET is shorted and the ISET pin is shorted to the GND. And as the ISET pin returns to a normal state, the LED
current returns.
○SSFB (13pin)
The SSFB pin is used to make setting of soft start time and duty for soft start, and DC/DC current mode control error
amplifier. It performs constant current charge of 10uA to the external capacitor connected to SSFB terminal, which enables
soft-start of DC/DC converter.
The SSFB pin detects the voltages of LED pins (1 to 4) and controls inductor current so that the pin voltage of the LED
located in the row with the highest Vf will come to 0.45V(ADIM=2.5V,ISET=50kΩ,ILED=150mA). As a result, the pin
voltages of other LEDs become higher by Vf variation. After completion of soft start, the SSFB pin is put into the
high-impedance state with the PWM signal being in the low state, thus maintaining the SSFB voltage.
Since the LED protection function (OPEN/SHORT detection) works when it turns to the LED feedback mode.
○RT (14pin)
The RT pin is used to connect a DC/DC frequency setting resistor. DC/DC drive frequency is determined by connecting the
RT resistor.
Drive frequency vs. RT resistance (Ideal)
R RT
15000
f SW [ kHz ]
[ k ]
When RT is 100kΩ, Fsw is 150kHz(typ.). However, drive frequency setting should be made in the range of 100 kHz to 800
kHz.
○ADIM (15pin)
ADIM pin is for analog dimming. Output current is proportionality with input voltage. Basically, ADIM pin assumes the
voltage inputted externally using high accuracy of resistive divider and etc., IC internally is in OPEN (High impedance)
condition. Cannot use in an OPEN condition.
If you don't use analog dimming, please connect pull-up resistor to over 5V (for example REG58).
○VCC (16pin)
The VCC pin is used to supply power for the IC in the range of 9 to 35V.
If the VCC pin voltage reaches 7.5V (Typ.) or more, the IC will initiate operation. If it reaches 7.2V (Typ.) or less, the IC will
be shut down.
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BD93942F
Startup operation and soft start (SSFB) capacitance setting
The following section describes the sequence for the startup of this IC.
①
10uA
5V
VOUT
Q D
PWM
COMP
STB
Soft-Start(ISS=10uA)
IFB(Sink, Source)=±100uA)
DRIVER
OSC
OSC
CS
ILED
SSFB
N
PWM
LED
SSFB
②
RSSFB
VOUT
ILED
LED_OK
VLED
CSSFB
③
PWM=L:STOP
N
LED_OK
PWM
LED_DRIVER
④
⑤
⑥
Figure 12. Circuit behavior at startup
Figure 11. Startup waveform
Description of startup sequence
(1) Set the STB and PWM pin to “ON”.
(2) Set all systems to “ON”, SSFB charge will be initiated.
(3) Since the SSFB pin reach the lower limit of the internal sawtooth wave of the IC, the DC/DC converter operates to
start VOUT voltage rising.
(4) The Vout voltage continues rising to reach a voltage at which LED current starts flowing.
(5) When the LED current reaches the set amount of current, the startup operation is completed.
(6) After that, conduct normal operation following the feedback operation sequence with the LED pins.
If the SSFB pin sink/source current is ±100uA, the LED protection function will be activated.
SSFB capacitance setting procedure
As aforementioned, this IC stops DC/DC converter when the PWM pin is set to Low level and conducts step-up operation
only in the section in which the PWM pin is maintained at High level. Consequently, setting the PWM duty cycle to the
minimum will extend the startup time. The startup time also varies with application settings of output capacitance, LED
current, output voltage, and others.
Startup time at minimum duty cycle can be approximated according to the following method:
Make maeasurement of VOUT startup time with a 100% duty cycle, first. Take this value as “Trise100”.
The startup time “Trise_min” for the relevant application with the minimum duty cycle is given by the following equation.
Trise _ min
Trise _100[Sec]
Min _ Duty [ratio]
[Sec]
However, since this calculation method is just for approximation, use it only as a guide.
Assuming that the SSFB pin voltage is VSSFB, the time is given by the following equation:
TSSFB
CSSFB[ F ] VSSFB[V ]
10[A]
[Sec]
As a result, it is recommended to make SSFB capacitance setting so that “TSSFB” will be greater than “Trise_min”
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BD93942F
About unused LED terminal automatic detecting function
This IC is detected automatically that it is an unused channel by asssuming the LED terminal to be OPEN at starting. It
explains the sequence.
20us
GND
GND
Figure 14. Block diagram
Figure 13. Timming chart
Sequence;
① STB=PWM=ON
② All systems are ON and SSFB starts charging.
③ When the output voltage is boosted enough, and enough current flows through the LED, LED_OK signal is switched
in the IC. PWM=L from the Rise timing of this signal for about 20us
④ During this PWM=L period, LED pins with LED connections' output voltage becomes 0.2V and above, where as
unused LED pins are below 0.2V.
⑤ During this time, determination on whether the LED pins are 0.2V above/below is done.
⑥ After the determination, unused LED pins are pulled up to 5V.
⑦The AUTO timer don’t count.
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BD93942F
LED current setting
Setting of LED output current “ILED” can be made by connecting a resistor RISET to the ISET pin.
RISET vs. ILED current relation equation
R ISET
7500
[ k]
I LED [ mA]
(ADIM=2.5V)
However, LED current setting should be made in the range of 30mA to 150mA.
[Setting example]
To set ILED current to 100mA, RISET resistance is given by the following equation:
R ISET
7500
7500
75 [k]
I LED [mA] 100[ mA]
DC/DC converter drive frequency setting
DC/DC converter drive frequency is determined by making RT resistance setting.
Drive frequency vs. RT resistance (ideal) relation equation
R RT
15000
f SW [ kHz ]
[ k ]
where fsw DC/DC converter oscillation frequency [kHz]
This equation has become an ideal equation without any correction item included.
For accurate frequency settings, thorough verification should be performed on practical sets.
[Setting example]
To set DC/DC drive frequency “fsw” to 200 kHz, RRT is given by the following equation:
RRT
15000
15000
75 [ k]
f sw [ kHz ] 200[ kHz ]
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BD93942F
OVP/SCP Settings
OVP pin is DC/DC output voltage’s over voltage protection and short circuit protection input pin.
OVP pin is a high impedance pin with no pull down resistor. Thus, at OPEN state please set the voltage
input settings using voltage dividing resistor and such.
Respective OVP pin protection conditions are as below
Protection
Name
Detection
Pin
Detection
Condition
Cancellation
Condition
OVP
OVP
OVP>3.0V
OVP0.45 it stops the DCDC. Thus, RCS resistor value
need to be checked after the peak current flow through the inductor is calculated. Furthermore, DCDC external
components’ current capacity needs to be greater than peak current flowing through this inductor.
（Inductor peak current Ipeak calculation method）
Firstly, ripple voltage which occurs at the CS pin is decided depending on the DCDC application conditions.
The conditions when made as below;
Output voltage=VOUT[V]
LED total current=IOUT[A]
DCDC input voltage=VIN[V]
DCDC efficiency =η[%]
Total required average input current IIN:
I IN
VOUT [V ] I OUT [ A]
[ A]
VIN [V ] [%]
Inductor ripple current IL[A] which occurs at inductor L[H] during
DCDC drive operation with switching frequency=fsw[Hz] is as follows
Δ IL
(VOUT [V ] V IN [V ]) V IN [V ]
[ A]
L[ H ] VOUT [V ] f SW [ Hz ]
Figure 17. DC/DC convertor application circuit
Therefore, IL’s peak current Ipeak can be calculated using below equation
Ipeak I IN [ A]
IL[ A]
2
[ A] (1)
(Resistor RCS connected to CS pin selection method)
This Ipeak flows in RCS and generates voltage. (refer to time chart
diagram on the right). This voltage value, VCSpeak can be calculated as below
VCS peak Rcs Ipeak
[V ]
This VCSpeak when reach 0.45V, will stop the DCDC output.
Thus when selecting RCS value, below condition needs to be met.
Rcs [ ] Ipeak [ A] 0.45[V ]
(DCDC Components’ Current Capacity Selection Method)
When OCP reach detection voltage CS=0.45V, Iocp current
I OCP
0.45[V ]
[ A] ( 2 )
Rcs[ ]
Figure 18. Inductor current waveform
Ipeak current (1)、IOCP current (2)、and components’ MAX current capacity needs to satisfy the following
I peak I OCP
Rated current of components
Above condition needs to be satisfied when selecting DCDC application parts eg. FET, inductor, diode etc.
Furthermore, continuous mode is recommended for normal DCDC applications. Inductor’s ripple current MIN limit value,
lmin becoming
Im in I IN [ A]
IL[ A]
[ A] 0
2
Is a condition to be met. If this is not met, it is called discontinuous mode.
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BD93942F
【Setting Example】
Output voltage=VOUT[V]=56V
LED total current=IOUT[A]=100mA×4ch=0.40A
DCDC input voltage=VIN[V]=14V
DCDC efficiency=η[%]=90%
Total required average input current IIN:
I IN [ A]
VOUT [V ] I OUT [ A] 56[V ] 0.40[ A]
1.78 [ A]
14[V ] 90[%]
VIN [V ] [%]
When, DCDC switching frequency =fsw[Hz]=200kHz
Inductor L[H]=33uH,
Inductor ripple current ΔIL[A]:
Δ IL
(VOUT [V ] V IN [V ]) V IN [V ]
(56[V ] 14[V ]) 14[V ]
1.59 [ A]
L[ H ] VOUT [V ] f SW [ Hz ]
33 10 6 [ H ] 56[V ] 200 10 3 [ Hz ]
Thus, IL peak current Ipeak becomes
Ipeak I IN [ A]
IL[ A]
1.59[ A]
[
A] 1.78[ A]
2.58 [ A]
2
2
…Peak current calculation result
RCS resistor value when set at 0.1ohm
VCS
peak
Rcs Ipeak 0 . 10 [ ] 2 . 58 [ A ] 0 . 258
[V ] 0 . 45V
…RCS resistor consideration
and satisfy the condition.
In addition、OCP detection current IOCP at this time is
I OCP
0.45[V ]
4 . 5 [ A]
0.1[ ]
If parts used (FET,INDUCTOR、DIODE etc)’s current capacity 0.2V
2
LED SHORT
LEDｘ
LEDx > 5V
H
After
LED_OK
LEDx < 5V
2
LED
GND SHORT
LEDｘ
LEDx < 0.2V
and
SSFB > 4.0V
H
-
LEDx > 0.2V
or
SSFB < 3.6V
ISET
GND SHORT
ISET
-
-
REG58 UVLO
REG58
REG582.6V
VCC UVLO
VCC
VCC7.5V
OVP
OVP
OVP>3.0V
-
-
OVP0.45V
-
Above
ISET×90%
-
-
Protection Type
12
count
12
count
Immediately
Auto-Restart
after detection
(Judge
periodically
whether normal
or not)
Immediately
Auto-Restart
after detection
(Judge
periodically
whether normal
or not)
12
7
(2 +2 ) count
Latch
Immediately
Detect
Auto-Restart
Immediately
Detect
Immediately
Detect
Immediately
Detect
12
2 count
Immediately
Detect
Auto-Restart
Auto-Restart
Auto-Restart
Auto-Restart
Pulse-by-Pulse
To clear the latch type, STB should be set to “L” once, and then to “H”.
Operation after the protection function detected
Protection Function
DC/DC
LED OPEN
Continue to operate
LED SHORT
Continue to operate
LED GND SHORT
Stop
after (CP+27) count
ISET GND SHORT
Stop immediately
STB
Stop immediately
REG58 UVLO
Stop immediately
VCC UVLO
Stop immediately
Stop immediately
(N pin only)
Stop immediately
(N pin only)
N pin limits DUTY
OVP
SCP
OCP
LED Driver
Only detected LED ch
stops after CP count
Only detected LED ch
stops after CP count
Only detected LED ch
stops after CP count
Other LED ch stop operation
7
after (CP+2 ) count
Soft-start
Continue to operate
Continue to operate
Discharge
after (CP+27) count
Stop immediately
Stop
(and when REG58 Pin A and GND > Pin B, the P-N junction operates as a parasitic diode.
When GND > Pin B, the P-N junction operates as a parasitic transistor.
Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual
interference among circuits, operational faults, or physical damage. Therefore, conditions that cause these diodes to
operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should
be avoided.
Figure 23. Example of monolithic IC structure
12.
Ceramic Capacitor
When using a ceramic capacitor, determine the dielectric constant considering the change of capacitance with
temperature and the decrease in nominal capacitance due to DC bias and others.
13. Area of Safe Operation (ASO)
Operate the IC such that the output voltage, output current, and power dissipation are all within the Area of Safe
Operation (ASO).
14. Thermal Shutdown Circuit(TSD)
This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always
be within the IC’s power dissipation rating. If however the rating is exceeded for a continued period, the junction
temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls below
the TSD threshold, the circuits are automatically restored to normal operation.
Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no
circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from
heat damage.
15. Over Current Protection Circuit (OCP)
This IC incorporates an integrated overcurrent protection circuit that is activated when the load is shorted. This
protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the IC should
not be used in applications characterized by continuous operation or transitioning of the protection circuit.
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Datasheet
BD93942F
Ordering Information
B
D
9
3
9
4
2
F
-
Part Number
E2
Packaging and forming specification
E2: Embossed tape and reel
Marking Diagrams
SOP16(TOP VIEW)
Part Number Marking
BD93942F
LOT Number
1PIN MARK
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Datasheet
BD93942F
Physical Dimension, Tape and Reel Information
Package Name
SOP16
(Max 10.35 (include.BURR))
(UNIT : mm)
PKG : SOP16
Drawing No. : EX114-5001
Tape
Embossed carrier tape
Quantity
2500pcs
Direction
of feed
E2
The direction is the 1pin of product is at the upper left when you hold
( reel on the left hand and you pull out the tape on the right hand
Direction of feed
1pin
Reel
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BD93942F
Revision History
Date
Revision
Changes
12.Feb.2015
001
New release
12.Aug.2015
002
p.3 [REG58 Block]
Soft start completion voltage -> REG58 available current
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Datasheet
Notice
Precaution on using ROHM Products
1.
Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,
OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you
(Note 1)
, transport
intend to use our Products in devices requiring extremely high reliability (such as medical equipment
equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car
accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or
serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.
Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any
damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific
Applications.
(Note1) Medical Equipment Classification of the Specific Applications
JAPAN
USA
EU
CHINA
CLASSⅢ
CLASSⅡb
CLASSⅢ
CLASSⅢ
CLASSⅣ
CLASSⅢ
2.
ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor
products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate
safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which
a failure or malfunction of our Products may cause. The following are examples of safety measures:
[a] Installation of protection circuits or other protective devices to improve system safety
[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure
3.
Our Products are designed and manufactured for use under standard conditions and not under any special or
extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way
responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any
special or extraordinary environments or conditions. If you intend to use our Products under any special or
extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of
product performance, reliability, etc, prior to use, must be necessary:
[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents
[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust
[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,
H2S, NH3, SO2, and NO2
[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves
[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items
[f] Sealing or coating our Products with resin or other coating materials
[g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of
flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning
residue after soldering
[h] Use of the Products in places subject to dew condensation
4.
The Products are not subject to radiation-proof design.
5.
Please verify and confirm characteristics of the final or mounted products in using the Products.
6.
In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,
confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power
exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect
product performance and reliability.
7.
De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual
ambient temperature.
8.
Confirm that operation temperature is within the specified range described in the product specification.
9.
ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in
this document.
Precaution for Mounting / Circuit board design
1.
When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product
performance and reliability.
2.
In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must
be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products,
please consult with the ROHM representative in advance.
For details, please refer to ROHM Mounting specification
Notice-PGA-E
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Datasheet
Precautions Regarding Application Examples and External Circuits
1.
If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the
characteristics of the Products and external components, including transient characteristics, as well as static
characteristics.
2.
You agree that application notes, reference designs, and associated data and information contained in this document
are presented only as guidance for Products use. Therefore, in case you use such information, you are solely
responsible for it and you must exercise your own independent verification and judgment in the use of such information
contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses
incurred by you or third parties arising from the use of such information.
Precaution for Electrostatic
This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper
caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be
applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,
isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).
Precaution for Storage / Transportation
1.
Product performance and soldered connections may deteriorate if the Products are stored in the places where:
[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2
[b] the temperature or humidity exceeds those recommended by ROHM
[c] the Products are exposed to direct sunshine or condensation
[d] the Products are exposed to high Electrostatic
2.
Even under ROHM recommended storage condition, solderability of products out of recommended storage time period
may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is
exceeding the recommended storage time period.
3.
Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads
may occur due to excessive stress applied when dropping of a carton.
4.
Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of
which storage time is exceeding the recommended storage time period.
Precaution for Product Label
QR code printed on ROHM Products label is for ROHM’s internal use only.
Precaution for Disposition
When disposing Products please dispose them properly using an authorized industry waste company.
Precaution for Foreign Exchange and Foreign Trade act
Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign
trade act, please consult with ROHM in case of export.
Precaution Regarding Intellectual Property Rights
1.
All information and data including but not limited to application example contained in this document is for reference
only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any
other rights of any third party regarding such information or data.
2.
ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the
Products with other articles such as components, circuits, systems or external equipment (including software).
3.
No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any
third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM
will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to
manufacture or sell products containing the Products, subject to the terms and conditions herein.
Other Precaution
1.
This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.
2.
The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written
consent of ROHM.
3.
In no event shall you use in any way whatsoever the Products and the related technical information contained in the
Products or this document for any military purposes, including but not limited to, the development of mass-destruction
weapons.
4.
The proper names of companies or products described in this document are trademarks or registered trademarks of
ROHM, its affiliated companies or third parties.
Notice-PGA-E
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Datasheet
General Precaution
1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.
ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny
ROHM’s Products against warning, caution or note contained in this document.
2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior
notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s
representative.
3.
The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all
information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or
liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or
concerning such information.
Notice – WE
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