VIPER16LD STMicroelectronics, VIPER16LD Datasheet - Page 14
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VIPER16LD
Manufacturer Part Number
VIPER16LD
Description
IC OFFLINE CONV PWM OTP 16-SOIC
Manufacturer
STMicroelectronics
Series
VIPer™ plusr
Datasheet
1.VIPER16HDTR.pdf
(24 pages)
Specifications of VIPER16LD
Output Isolation
Either
Frequency Range
54 ~ 66kHz
Voltage - Input
11.5 ~ 23.5 V
Voltage - Output
800V
Power (watts)
12W
Operating Temperature
-40°C ~ 150°C
Package / Case
16-SOIC (0.154", 3.90mm Width)
Switching Frequency
60 KHz
Mounting Style
SMD/SMT
Duty Cycle (max)
80 %
For Use With
497-9006 - BOARD EVAL BASED ON VIPER16497-8838 - EVAL BOARD FOR VIPER16LD497-8837 - EVAL BOARD FOR VIPER16LD ISO PSU
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
VIPER16LDTR
Manufacturer:
STM
Quantity:
2 188
Part Number:
VIPER16LDTR
Manufacturer:
ST
Quantity:
20 000
Oscillator
9
10
11
14/24
Oscillator
The switching frequency is internally fixed at 60 kHz (part number VIPER16LN or LD) or 115
kHz (part number VIPER16LN or LD).
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
on
after a fault event.
This function helps prevent transformers' saturation during start-up and short-circuit.
Adjustable current limit set point
The VIPer16 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
Table 8 on page
7, and the function is activated for any attempt of converter start-up and
Dlim
Dlim
, see
Doc ID 15232 Rev 4
, 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
. By this way the drain current is
, see typical value
3. As soon as the sensed
9.
Figure 2 on page
7.
3, checks
VIPER16