VIPER26 STMicroelectronics, VIPER26 Datasheet - Page 14

no-image

VIPER26

Manufacturer Part Number
VIPER26
Description
VIPerPlus family: fixed frequency high performance off line high voltage converter
Manufacturer
STMicroelectronics
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
VIPER26HN
Manufacturer:
MSC
Quantity:
1 200
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
VIPER26LD
Manufacturer:
STMicroelectronics
Quantity:
1 910
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
VIPER26LDTR
Manufacturer:
ST
Quantity:
4 500
Price:
Company:
Bonase Electronics (HK) Co., Limited Bonase Electronics (HK) Co., Limited
Part Number:
VIPER26LN
Manufacturer:
STMicroelectronics
Quantity:
1 977
Price:
Oscillator
9
10
11
14/25
Oscillator
The switching frequency is internally fixed at 60 kHz (VIPER26LN or LD) or 115 kHz
(VIPER26HN or HD).
In both cases the switching frequency is modulated by approximately ±4 kHz (60 kHz
version) or ±8 kHz (115 kHz version) at 230 Hz (typical) rate, so that the resulting spread-
spectrum action distributes the energy of each harmonic of the switching frequency over a
number of sideband harmonics having the same energy on the whole but smaller
amplitudes.
Soft start-up
During the converters' start-up phase, the soft-start function progressively increases the
cycle-by-cycle drain current limit, up to the default value I
further limited and the output voltage is progressively increased reducing the stress on the
secondary diode. The soft-start time is internally fixed to t
page
event.
This function helps prevent transformers' saturation during start-up and short-circuit.
Adjustable current limit set point
The VIPer26 includes a current mode PWM controller: cycle by cycle the drain current is
sensed through the integrated resistor R
inverting input of the PWM comparator, see
voltage is equal to the voltage derived from the COMP pin, the power MOSFET is switched
OFF.
In parallel with the PWM operations, the comparator OCP, see
the level of the drain current and switch OFF the power MOSFET in case the current is
higher than the threshold I
The level of the drain current limit, I
from the pin LIM. The resistor R
than the level of the current limit, I
When the LIM pin is left open or if the R
is fixed to its default value, I
7, and the function is activated for any attempt of converter start-up and after a fault
Dlim
Dlim
, see
Doc ID 17736 Rev 2
, as reported on
LIM
Dlim
, between LIM and GND pins, fixes the current sunk and
Dlim
Table 8 on page
, see
, can be reduced depending from the sunk current
LIM
SENSE
Figure 13 on page
has an high value (i.e. > 80 kΩ) the current limit
Figure 2 on page
and the voltage is applied to the non
Table 8 on page
7.
Dlim
SS
, see typical value on
. By this way the drain current is
3. As soon as the sensed
9.
Figure 2 on page
7.
Table 8 on
3, checks
VIPER26

Related parts for VIPER26