m51996ap Renesas Electronics Corporation., m51996ap Datasheet - Page 16

• Manufacturer Part Number: m51996ap
• Description: Switching Regulator Control
• Manufacturer: Renesas Electronics Corporation.

M51996AP/AFP
REJ03D0836-0201 Rev.2.01 Nov 14, 2007
Page 16 of 35
Figure 5 shows the relationship between oscillator waveform and output pulse.
If the SOFT terminal voltage is V
The fall rate of oscillation waveform is given as
≈
≈
Where
V
V
If V
If V
Figure 6 Relationship Between Oscillator Waveform and Output Waveform at Start-up
SOFT
BE
V
R
R
SOFT
SOFT
SOFT
ON
V
OFF
0.65 V
T-ON
; SOFT terminal applied voltage
× C
− V
× C
V
V
Waveform of CF terminal
F
BE
BE
Figure 5 Oscillator Waveform When the SOFT Circuit is Operating
BE
F
(V/s) ………………………………………… (5)
Voltage waveform of
CF Terminal
Waveform of V
terminal in Max
ON duty condition
+
0, V
V
Waveform of V
terminal in Max
ON duty condition
16 × R
T-OFF
SOFT
V
( 3.5 V), V
T-ON
ON
× C
V
SOFT
OUT
BE
F
OUT
, the rise rate of CF terminal given as
V
V
(V/s) ………………… (6)
0
OSCH
OSCL
V
V
SOFT
OH
OL
≈ 4.4 V
≈ 2.0 V
0
0
V
V
OSCH
OSCL
V
V
OH
OL
Operation start
V
No output
pulse
BE
V
T-OFF
Start from 0 V
The first
output pulse
t
t
t
t