ALTAIR05T-800TR STMicroelectronics, ALTAIR05T-800TR Datasheet - Page 12

• Manufacturer Part Number: ALTAIR05T-800TR
• Description: Switching Converters, Regulators & Controllers 800V Off-line QR Switching Regulator
• Manufacturer: STMicroelectronics

Specifications of ALTAIR05T-800TR

• Input Voltage: 11.5 V to 23 V
• Switching Frequency: 166 KHz
• Operating Temperature Range: - 55 C to + 150 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-16
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application information
5.1
5.2
12/28
Power section and gate driver
The power section guarantees safe avalanche operation within the specified energy rating
as well as high dv/dt capability. The Power MOSFET has a V
typical R
The gate driver is designed to supply a controlled gate current during both turn-on and turn-
off in order to minimize common mode EMI. Under UVLO conditions an internal pull-down
circuit holds the gate low in order to ensure that the power MOSFET cannot be turned on
accidentally.
High-voltage start-up generator
The HV current generator is supplied through the DRAIN pin and it is enabled only if the
input bulk capacitor voltage is higher than V
current generator is ON, the Icharge current (5.5 mA typical value) is delivered to the
capacitor on the V
With reference to the timing diagram of
the voltage on the input bulk capacitor is high enough, the HV generator is sufficiently
biased to start operating, thus it draws about 5.5 mA (typical) from the bulk capacitor. Most
of this current charges the bypass capacitor connected between the Vcc pin and ground and
make its voltage rise linearly.
As the Vcc voltage reaches the start-up threshold (13 V typ.) the chip starts operating, the
internal power MOSFET is enabled to switch and the HV generator is cut off. The IC is
powered by the energy stored in the Vcc capacitor.
The chip is able to power itself directly from the rectified mains: when the voltage on the V
pin falls below Vcc
generator is turned on and charges the supply capacitor until it reaches the V
threshold.
In this way, the self-supply circuit develops a voltage high enough to sustain the operation of
the device. This feature is useful especially during CC regulation, when the flyback voltage
generated by the auxiliary winding alone may not be able to keep Vcc above V
At converter power-down the system loses regulation as soon as the input voltage falls
below V
voltage decay at system power-down.
Start
DS(on)
. This prevents converter’s restart attempts and ensures monotonic output
of 11 Ω.
CC
restart
pin.
(10.5V typ.), during each MOSFET’s off-time the HV current
Doc ID 17957 Rev 1
Figure
start
10, when power is applied to the circuit and
threshold, 50 V
(BR)DSS
DC
typically. When the HV
of 800 V min. and a
ALTAIR05T-800
CCOn
CCrestart
.
CC