L6699DTR STMicroelectronics, L6699DTR Datasheet - Page 14

• Manufacturer Part Number: L6699DTR
• Description: AC/DC Switching Converters Enhanced High Volt Res CTRL 600V
• Manufacturer: STMicroelectronics

Specifications of L6699DTR

• Product Category: AC/DC Switching Converters

Application information
14/38
After fixing CF according to
Table 6.
Value of RF
entire range needed for regulation, from the minimum value f
and maximum load) to the maximum value f
load):
Equation 2
Figure 6.
A different selection criterion is given for RF
Section 7: Operation at no load or very light load
In
signal, as well as the midpoint of the half bridge leg (HB) is shown. Note that the low-side
gate-drive is turned on while the oscillator's triangle is ramping up and the high-side gate-
drive is turned on while the triangle is ramping down. In this way, at startup, or as the IC
resumes switching during burst-mode operation, the low-side MOSFET is switched on first
to charge the bootstrap capacitor. As a result, the bootstrap capacitor is always charged and
ready to supply the high-side floating driver (see
Figure 6
f
190 – 200
start
150
160
170
180
210
220
[kHz]
the timing relationship between the oscillator waveform and the gate-drive
min
Recommended values for CF as a function of the startup frequency f
Oscillator waveforms and their relationship with gate-driving signals
and RF
HVG
LVG
HB
CF
max
RF
mi n
is selected so that the oscillator frequency is able to cover the
Table 6
Doc ID 022835 Rev 2
=
CF [pF]
· 3
T
680
560
470
390
330
270
220
D
:
CF
1
f ·
T
D
min
max
max
;
if burst-mode operation is to be used (see
(at maximum input voltage and minimum
).
Section 12: Bootstrap section
RF
f
start
230 - 240
max
250
260
270
280
290
300
[kHz]
=
f
f
min
RF
max
min
(at minimum input voltage
min
-
1
t
t
t
t
CF [pF]
).
180
150
120
100
82
68
56
AM11380v1
L6699
start