Quasi-Resonant Control DC/DC
converter and Power Factor Correction
converter IC for AC/DC Converter
BM1051F is compounded LSI of Power Factor Correction
converter (PFC) for harmonic solution and DC/DC converter
(DC/DC). Because DC/DC operates on Quasi-resonant
method, DC/DC contributes to Low EMI.
BM1051F built in a HV starter circuit that tolerates 650V.
Because of putting the current sense resistors externally
both the PFC part and the DC/DC part, IC enables power
supply design free.
In the PFC part, IC adopts peak current control operation.
Suitable application is proposed by a various protection
circuit, such as the multiplier with a revision circuit on the AC
voltage falls, the load regulation revision circuit, and the
maximum power feed-forward circuit, etc.
The Quasi-resonant system of a DC/DC part contributes to
low EMI because PFC operates by soft switching.
A burst mode is built in, so the power is reduced at light load.
Various protection functions, such as a soft start function, a
burst function, an over-current limiting for every cycle,
overvoltage protection, and over current protection, are built
in. The pin for communicated control with a controller and the
external stop pin are prepared; it proposes the system that
can be adapted for various applications.
Operating Power Supply Voltage Range:
VCC：8.0 to 24.0V
QR ON (PFC OFF)：1.20mA(pulse on)
QR ON (PFC OFF)：1.00mA(pulse off)
QR ON (PFC ON)：1.80mA(pulse on)
Oscillation Frequency QR part :120kHz(FB=2.0V typ)
Operating Temperature: -40℃ to +85℃
●Typical Application Circuit(s)
QR_ZT QR_FB QR_CS
Quasi-resonant circuit + PFC circuit
Built-in HV Starter circuit
Low consumption current (typ.10uA) when starter
circuit is OFF.
Quasi resonant circuit
Max operating frequency(120kHz)
Frequency reduction function
Over-current limiting variable function
Pulse-by-pulse over-current protection circuit
Built-in Soft start
Voltage protection function (brown out) during low
ZT pin Over Voltage Protection
Output overload protection (auto recovery /latch
250nsec Leading-Edge Blanking
Power Factor Correction circuit
Peak current control (65kHz)
Per-cycle over current protection circuit
Maximum power revision
the multiplier with a revision circuit when the AC
the load change measure circuit
Selectable protection method by LATCH/AUTOR
LATCH/AUTOR=H : Latch
LATCH/AUTOR=L : Auto recovery
External stop function (COMP pin)
AC input voltage stop detected function (ACDET)
Built-in PFC stop terminal (PFCON/OFF)
SOP24 15.0mm×5.40mm ×1.80mm pitch1.27mm
(Typ.) (Typ.) (TYP.) （TYP.）
TV, AC adapters, printers, LED lighting
Figure 1. Application circuit
○Product structure：Silicon monolithic integrated circuit
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