VIPER53SP STMicroelectronics, VIPER53SP Datasheet - Page 17

• Manufacturer Part Number: VIPER53SP
• Description: IC OFFLINE SWIT PWM CM POWERSO10
• Manufacturer: STMicroelectronics
• Series: VIPER™r

Specifications of VIPER53SP

• Output Isolation: Isolated
• Frequency Range: 93 ~ 300kHz
• Voltage - Input: 8.4 ~ 19 V
• Voltage - Output: 620V
• Power (watts): 40W
• Operating Temperature: 25°C ~ 125°C
• Package / Case: PowerSO-10 Exposed Bottom Pad
• For Use With: 497-8435 - BOARD EVAL FOR VIPER53 28W497-6458 - BOARD EVAL BASED ON VIPER53-E497-6262 - BOARD REF SGL VIPER53 90-264VAC497-5866 - EVAL BOARD 24W NEG OUT VIPER53E497-4933 - BOARD PWR SUPPLY 24W OUTPUT VIPE
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-3289-5

introducing a zero and ensuring a correct phase
margin. This configuration is illustrated in figure 18
Figure 19: Typical Transfer Functions
amplifier transfer function for a typical set of values
for C
10 nF (minimum value: 8 nF) should always be
connected to the COMP pin to insure a correct
stability of the internal error amplifier.
The complete converter open loop transfer
function can be built from both power cell and error
amplifier transfer functions. A theoretical example
can be seen in figure 20 for a discontinuous mode
flyback loaded by a simple resistor, regulated from
primary side (no optocoupler, the internal error
amplifier is fully used for regulation). A typical
schematic corresponding to this situation can be
seen on figure 14.
COMP
and R
COMP
Gain (dB)
Phase (°)
-100
-10
. Note that a capacitor of
-10
-20
-30
-40
-50
-60
-70
-80
-90
60
50
40
30
20
10
0
0
1
1
10
10
100
100
Frequency (Hz)
Frequency (Hz)
1k
1k
for the schematic and figure 19 for the error
The transfer function of the power cell is
represented as G(s) in figure 20. It exhibits a pole
which depends on the output load and on the
output capacitor value. As the load of a converter
may change, two curves are shown for two
different values of output resistance value, R
R
appears, due to the output capacitor ESR. Note
that the overall transfer function doesn’t depend on
the input voltage, thanks to the current mode
control.
The error amplifier has a fixed behavior, similar to
the one shown in figure 19. Its bandwidth is limited,
in order to avoid injection of high frequency noise
L2
. A zero at higher frequency values then
10k
10k
100k
100k
Rcomp=4.7k
Ccomp=470nF
Rcomp=4.7k
Ccomp=470nF
VIPer53DIP / VIPer53SP
1M
1M
L1
17/24
and