Ricoh RH5RH13B - Manual (Page 30)

26
V IN
Inductor
Diode
OUT
Vss
V OUT
+
Capacitor
EXT
ZD:6.8V
RH5RH502B
Tr
Cb
R ZD
Rb
Starter Circuit
(Note) When the Output Current is small or the Output Voltage is unstable,use the Rzd for flowing the bias current through the Zener diode ZD.
FIG. 6
V IN
Inductor
Diode
OUT
Vss
V OUT
+
Capacitor
RH5RH
××
1A
Tr PNP
Lx
Rb1
Rb2
Starter Circuit
(Note) When the L X pin Voltage is over the rating at the time PNP Tr is OFF,use a RH5RH
××
2B and drive the PNP Tr. by the external NPN Tr.
FIG. 7
APPLICATION CIRCUITS
• 12V Step-up Circuit
RH5RH
• Step-down Circuit