HF81 Datasheet, PDF (1/10 Pages) Monolithic Power Systems – X Capacitor Bleeder

The Future of Analog IC Technology
DESCRIPTION
HF81 is an innovative two-terminal IC that
automatically discharges an X capacitor while
eliminating power losses and allowing power
supplies to comply with safety standards.
The HF81 acts as a smart high-voltage switch
when placed in series with discharge resistors
(alternatively bleed resistors). In the presence
of an AC voltage, the HF81 blocks current flow
in the safety discharge resistors to reduce the
power loss in these components to zero at 230
VAC. When disconnected from the AC voltage,
the HF81 automatically and safely discharges
the X capacitor by closing the circuit through
the bleed resistors and directing the energy
away from the exposed AC plug.
Table 1: Component Selection Table
PN
X
Total Series
Capacitance Resistance
≤500nF
750nF
1.5MΩ
1MΩ
1μF
780kΩ
HF81
1.5μF
2μF
480kΩ
360kΩ
2.5μF
300kΩ
3.5μF
5μF
200kΩ
150kΩ
Notes:
1) The values are calculated at Vin=265Vac
Power
Saving⁽¹⁾
66mW
86mW
142mW
191mW
230mW
347mW
464mW
TYPICAL APPLICATION
HF81
X Capacitor Bleeder
FEATURES
 Disconnect series discharge resistors from
L-N when AC voltage is applied
 Connect series discharge resistors with L-N
to discharge the X capacitor when AC
voltage is unplugged
 Supplied by AC voltage directly and doesn’t
need external bias
 Meets safety standards for use before or
after input fuse
 No external ground pin leads to high
common mode surge immunity
 1000V internal JFET inside leads to high
differential surge immunity
 >4mm creepage on package and PCB
APPLICATIONS
 AC/DC converters with X capacitors larger
than 0.1μF
 All converters requiring ultra-low no-load
consumption and low standby power
 Appliances requiring EuP Lot 6 compliance
 Appliances requiring Energy Star V2.0
 White Goods (For example, Dishwasher,
Washing Machine, Air-Conditioner and etc.)
 Server Power, Telecom Power, ATX Power
All MPS parts are lead-free and adhere to the RoHS directive. For MPS green
status, please visit MPS website under Quality Assurance. “MPS” and “The
Future of Analog IC Technology” are Registered Trademarks of Monolithic
Power Systems, Inc.
HF81 Rev. 1.12
www.MonolithicPower.com
1
11/15/2012
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