MIC4680_08 Datasheet, PDF (8/15 Pages) Micrel Semiconductor – 1A 200kHz SuperSwitcher Buck Regulator

Micrel, Inc.
Functional Diagrams
SHDN
Internal
Regulator
V_IN
IN
200kHz
Oscillator
Thermal
Shutdown
Current
Limit
MIC4680
Com-
parator
Reset
Driver
SW
1A
Switch
FB
V_OUT
C_OUT
Error
Amp
MIC4680-x.x
1.23V
Bandgap
Reference
GND
Fixed Regulator
SHDN
Internal
Regulator
200kHz
Oscillator
Thermal
Shutdown
Current
Limit
V_IN
IN
V_OUT
= V_REF
⎛⎝⎜
R1
R2
+
1^{⎞⎠⎟}
R1
=
R2
⎛
⎝⎜
V_OUT
V_REF
-
⎞
1_⎠⎟
V_REF = 1.23V
Com-
parator
Reset
Driver
SW
1A
Switch
FB
Error
Amp
1.23V
Bandgap
Reference
MIC4680 [adj.]
V_OUT
C_OUT
R1
R2
Adjustable Regulator
March 2008
8
M9999-032808