tb62732fu TOSHIBA Semiconductor CORPORATION, tb62732fu Datasheet - Page 5

• Manufacturer Part Number: tb62732fu
• Description: Step-up Dc/dc Converter For White Led Driver
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Basic Operation
current pulse.
energy in the inductance.
and it reached IL = ILpeak = 350 (mA, typ.).
The step-up DC/DC converter is applied, and the basic circuit to the TB62732FU adopts peak control of the
The internal MOS transistor NMOS is turned on in the fixed frequency f
Inductance electric current IL turns off NMOS when it reaches 80% of 1/1 MHz when it increased from IL = 0
The shot key diode is turned on, and IL = Ic2 flows, because the coil may keep IL = ILpeak.
After that, Ic2 is decrease, and become IL = 0.
This operation is repeated, and Ic2 is fully done as to the charge, and it becomes I
The details of a basic pulse to use for the current control are shown in Figure 2.
0 (mA)
min
IL = ILpeak
SHDN
Figure 2 Switching Waveform of Inductance
Waveform of recommend
1.1 MHz
IL, ILpeak
V
inductance 1
CC
Figure 1 Application Circuit
T = 1/f
S
Maximum duty 85%
R
OSC
Q
, f
10 µH
OSC
GND
5
= 1.1 MHz (typ.)
Amp
Waveform of recommend
inductance 2
A
OSC
K
= 1 MHz, and the charge has the
Z
D
o
, and flows to LED.
Ic2
TB62732FU
2006-06-14
I
o=
I
f LED