Fujitsu MB39A105 manual Block Diagram

Page 4

MB39A105

BLOCK DIAGRAM

 

 

 

 

 

 

VCC

SCPOD

 

 

 

 

 

 

 

 

3

4

 

 

INE

1

VREF

 

 

 

 

 

 

 

 

 

 

Error Amp

PWM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+ Comp.

Drive

 

 

 

 

 

+

 

 

 

 

 

 

+

 

Nch

5

OUT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(0.5 V ± 1%)

 

 

 

 

FB

8

 

VREF

 

 

 

IO = 400 mA

 

 

 

 

 

 

 

(0.7 V)

6

GND

 

 

 

 

SCP

 

at VCC = 3.3 V

 

 

 

 

 

 

 

 

 

 

 

 

 

Comp.

+

(0.3 V)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(0.9 V)

 

 

 

 

CSCP

2

 

+

S

Q

 

 

 

 

 

 

(1.0 V)

 

 

 

 

 

 

 

 

 

RT Current

 

 

 

 

 

 

 

 

 

 

 

 

R

 

 

 

 

 

 

 

 

OSC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UVLO

 

 

 

bias

Power

 

 

 

 

 

 

 

VREF

ON/OFF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VREF

CTL

 

 

 

 

L : UVLO release

 

(1.27 V)

 

 

 

 

±10%

 

 

 

 

 

 

 

 

7

 

 

 

 

 

 

 

 

 

RT

 

 

 

4

Image 4
Contents Description FeaturesPackage PIN Assignment Pin No Symbol Descriptions PIN DescriptionBlock Diagram Parameter Symbol Condition Rating Unit Min Max Parameter Symbol Condition Value Unit Min TypAbsolute Maximum Ratings Recommended Operating ConditionsParameter Electrical CharacteristicsPin Conditions Value Unit Min Typ Max Typical Characteristics ErrorTriangularwave oscillation Power Dissipation vs. Ambient Temperature Error amplifier block Error Amp1, Error Amp2 FunctionsTriangular-wave oscillator block OSC PWM comparator block PWM CompPower Timer-latch short-circuit protection circuit SCPUnder voltage lockout protection circuit Uvlo Short-circuit protection detection output functionSetting the Output Voltage Setting the Triangular Oscillation FrequencySetting the SOFT-START Times Timer-latch short-circuit protection circuit MB39A105 Equivalent Circuit Application Parts List Parts NoSelection of Components 2I OV O 2LV O Peak-to-peak value ESR Reference Data Usage Precaution Ordering InformationDo not apply negative voltages Part number Package RemarksPackage Dimension IndexFujitsu Limited