VIPER28HN STMicroelectronics, VIPER28HN Datasheet - Page 24

• Manufacturer Part Number: VIPER28HN
• Description: IC OFFLINE CONV PWM OVP 8DIP
• Manufacturer: STMicroelectronics
• Series: VIPer™ plusr

Specifications of VIPER28HN

• Output Isolation: Isolated
• Frequency Range: 103 ~ 127kHz
• Voltage - Input: 8.5 ~ 23.5 V
• Voltage - Output: 800V
• Power (watts): 20W
• Operating Temperature: -25°C ~ 125°C
• Package / Case: 8-DIP (0.300", 7.62mm), 7 Leads
• Output Voltage: 800 V
• Output Power: 1 W
• Input Voltage: - 0.3 V
• Switching Frequency: 115 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: Through Hole
• Duty Cycle (max): 80 %
• Number Of Outputs: 1
• For Use With: 497-8840 - EVAL BOARD FOR VIPER28LD 60KHZ497-8839 - EVAL BOARD FOR VIPER28HD 115KHZ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-8391-5

Operation descriptions
7.12
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Extra power management function (EPT)
Some applications need an extra power for a limited time window during which the converter
regulation has to be guaranteed. The extra power management function allows to design a
converter that can satisfy this request and is provided by the EPT pin, see
page 8
This function requires the use of a capacitor on EPT pin (C
discharged by means of a 5 µA current cycle by cycle. When the drain current raises over
85% of Idlim value, see I
while when the drain current is below I
reaches the V
After the converter shut down, the V
threshold (typ. 14.5 V) and according to the auto restart operation
(see
threshold (typical, 4.5 V) in order to charge again the V
operation is enabled again only when the voltage on EPT pin, drop below the V
(typical, 0.6 V). The low C
ensures safe operations and avoids overheating in case of repeated overload events. The
value of C
can be connected to GND if the function is not used.
Section 7.5 on page 17
.
EPT
EPT
has to be selected in order to prevent the device overheating. The EPT pin
threshold (typical, 4 V), the converter is shut down.
DLIM_EPT
EPT
) the VDD pin voltage have to fall below the V
discharge current in combination with its low restart threshold,
Doc ID 15028 Rev 4
(
Table 8 on page 7
DD
DLIM_EPT
voltage will drop below the V
discharges the capacitor. If C
), the current generator charges C
DD
capacitor. Moreover the PWM
EPT
) that is charged or
DD(ON)
DD(RESTART)
Table 8 on
start up
EPT
EPT(RESTART)
‘s voltage
VIPER28
EPT