MB3775 Datasheet, PDF (11/25 Pages) Fujitsu Component Limited. – SWITCHING REGULATOR CONTROLLER

MB3775
s SYNCHRONIZATION OF ICs
To synchronize MB3775 ICs, first, the specified capacitor and resistor are connected to the CT and RT terminals of the master
IC to start self oscillation. Next, 2 V is applied to the RT terminals of the slave ICs to disable the charge/discharge circuit for
triangular wave oscillation. Finally, the CT terminals of the master and slave ICs are connected.
Instead of applying VRT to the RT terminals, these terminals can be pulled up by a resistor (see resistance indicated by the dashed
line in Fig. 8). Select the pull-up resistance Rpull from the formula given below.
VCC
0.5 x N
≤ Rpull
Rpull: Pull up Resistor (kΩ)
VCC: Power Supply Voltage (V)
N: Number of Slave ICs
Fig. 8 - Connection of Master, Slave
VCC
MB3775
(MASTER)
Rpull
CT
RT
MB3775
(SLAVE)
VRT
2V
MB3775
(SLAVE)
11