Kingbor Technology Co.,Ltd
KB3386
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
APPLICATION INFORMATION
regulation point for more than 32 cycles of
the internal clock, the KB3386 automati-
cally switches to the 2X mode. The KB3386
remains in the 2X mode until one of four
things happens: 1) the enable pin EN has
been toggled, 2) the Flash pin has changed
from high to low, 3) VIN is cycled or 4) a
thermal fault occurs. The 2X mode is the
chargepumpmodewheretheoutputcanbe
pumped as high as two times the input
voltage, provided the output does not ex-
ceed the maximum voltage for the KB3386,
which is internally limited to about 5.5V. In
the 2X mode, as in the 1X mode, the output
current is regulated by the voltage at the FB
pin.
_______________OVERTEMPERATURE
PROTECTION
When the temperature of the KB3386 rises
above 145 degrees Celsius, the over tem-
perature protection circuitry turns off the
output switches to prevent damage to the
device. If the temperature drops back down
below 135 degrees Celsius, the part auto-
matically recovers and executes a soft start
cycle.
In the Torch mode, (Flash = GND) the Flash
pin is set to logic low and the KB3386 FB pin
regulates to 50mV output:
____________________OVERVOLTAGE
PROTECTION
VFB = 50mV (Torch Mode)
When in Flash mode, (Flash = VIN), the FB
regulation voltage is set by the resistor RSET
connected between the RSET pin and SGND
and the equation:
The KB3386 has over voltage protection. If
the output voltage rises above the 5.5V
threshold, the over voltage protection shuts
off all of the output switches to prevent the
outputvoltagefromrisingfurther. Whenthe
output decreases below 5.5V, the device
VFB = (1.26V/ RSET)*11.2K1 (Flash Mode)
resumes normal operation
Where 1.26V is the internal bandgap refer-
ence voltage and 11.2K1 is an internal
resistance used to scale the RSET current.
Typical values of RSET are 40K1 to 180K1
for a range of VFB = 300mV to 75mV in Flash
mode.
____________________OVERCURRENT
PROTECTION
The over current protection circuitry moni-
tors the average current out of the VOUT
=
50mV (Torch Mode) pin. If the average
output current exceeds approximately
1Amp, then the over current protection cir-
cuitry shuts off the output switches to pro-
The output current is then set in either Flash
or Torch mode by the equation:
I
OUT = VFB / RSENSE
tect the chip.
Manufacturers/ Website
Part Number
Capacitance/
Voltage
Capacitor
Size/Type/Thickness 100KHz
ESR at
TDK/www.tdk.com
TDK/www.tdk.com
TDK/www.tdk.com
TDK/www.tdk.com
C1005X5R0J474K
C1005X5R0J105K
C1608X5R0J225K
C1608X5R0J475K
0.47uF/6.3V
1uF/6.3V
2.2uF/6.3V
4.7uF/6.3V
0.47uF/6.3V
1uF/6.3V
0402/X5R/0.55mm
0402/X5R/0.55mm
0603/X5R/0.9mm
0603/X5R/0.9mm
0402/X5R/0.55mm
0402/X5R/0.55mm
0603/X5R/0.8mm
0603/X5R/0.8mm
0.03
0.03
0.03
0.02
0.03
0.03
0.03
0.02
Murata/www.murata.com GRM155R60J474KE19D
Murata/www.murata.com GRM155R60J105KE19D
Murata/www.murata.com GRM188R60J225KE19D
Murata/www.murata.com GRM188R60J475KE19D
2.2uF/6.3V
4.7uF/6.3V
Table 1: Recommended Capacitors
6
KINGBOR [ KINGBOR TECHNOLOGY CO ]
