Datenblatt-pdf.com


Q0165R Schematic ( PDF Datasheet ) - Fairchild Semiconductor

Teilenummer Q0165R
Beschreibung FSQ0165R
Hersteller Fairchild Semiconductor
Logo Fairchild Semiconductor Logo 




Gesamt 24 Seiten
Q0165R Datasheet, Funktion
September 2007
FSQ0365, FSQ0265, FSQ0165, FSQ321, FSQ311
Green Mode Fairchild Power Switch (FPS™) for
Valley Switching Converter - Low EMI and High Efficiency
Features
„ Optimized for Valley Switching (VSC)
„ Low EMI through Variable Frequency Control and
Inherent Frequency Modulation
„ High-Efficiency through Minimum Voltage Switching
„ Narrow Frequency Variation Range over Wide Load
and Input Voltage Variation
„ Advanced Burst-Mode Operation for Low Standby
Power Consumption
„ Pulse-by-Pulse Current Limit
„ Various Protection Functions: Overload Protection
(OLP), Over-Voltage Protection (OVP), Abnormal
Over-Current Protection (AOCP), Internal Thermal
Shutdown (TSD)
„ Under-Voltage Lockout (UVLO) with Hysteresis
„ Internal Start-up Circuit
„ Internal High-Voltage SenseFET (650V)
„ Built-in Soft-Start (15ms)
Applications
„ Power Supply for DVP Player and DVD Recorder,
Set-Top Box
„ Adapter
„ Auxiliary Power Supply for PC, LCD TV, and PDP TV
Description
A Valley Switching Converter generally shows lower EMI
and higher power conversion efficiency than a
conventional hard-switched converter with a fixed
switching frequency. The FSQ-series is an integrated
Pulse-Width Modulation (PWM) controller and
SenseFET specifically designed for valley switching
operation with minimal external components. The PWM
controller includes an integrated fixed-frequency
oscillator, Under-Voltage Lockout, Leading Edge
Blanking (LEB), optimized gate driver, internal soft-start,
temperature-compensated precise current sources for
loop compensation, and self-protection circuitry.
Compared with discrete MOSFET and PWM controller
solutions, the FSQ-series reduces total cost, component
count, size and weight; while simultaneously increasing
efficiency, productivity, and system reliability. This device
provides a basic platform that is well suited for cost-
effective designs of valley switching fly-back converters.
Related Application Notes
„ AN-4137, AN-4141, AN-4147, AN-4150 (Flyback)
„ AN-4134 (Forward)
FPSTM is a trademark of Fairchild Semiconductor Corporation.
© 2006 Fairchild Semiconductor Corporation
FSQ0365, FSQ0265, FSQ0165, FSQ321, FSQ311 Rev. 1.0.5
www.fairchildsemi.com
Free Datasheet http://www.Datasheet4U.com






Q0165R Datasheet, Funktion
Electrical Characteristics
TA = 25°C unless otherwise specified.
Symbol
Parameter
SenseFET Section
BVDSS
IDSS
Drain Source Breakdown Voltage
Zero-Gate-Voltage Drain Current
FSQ0365
RDS(ON)
Drain-Source On-State
Resistance(13)
FSQ0265
FSQ0165
FSQ321/311
FSQ0365
CSS Input Capacitance
FSQ0265
FSQ0165
FSQ321/311
FSQ0365
COSS Output Capacitance
FSQ0265
FSQ0165
FSQ321/311
FSQ0365
CRSS
Reverse Transfer
Capacitance
FSQ0265
FSQ0165
FSQ321/311
FSQ0365
td(on)
Turn-On Delay Time
FSQ0265
FSQ0165
FSQ321/311
FSQ0365
tr Rise Time
FSQ0265
FSQ0165
FSQ321/311
FSQ0365
td(off)
Turn-Off Delay Time
FSQ0265
FSQ0165
FSQ321/311
FSQ0365
tf Fall Time
FSQ0265
FSQ0165
FSQ321/311
Control Section
tON.MAX1
tON.MAX2
tB1
tB2
Maximum On Time1
Maximum On Time2
Blanking Time1
Blanking Time2
All but Q321
Q321
All but Q321
Q321
Condition
VCC = 0V, ID = 100µA
VDS = 560V
TJ = 25°C, ID = 0.5A
VGS = 0V, VDS = 25V, f = 1MHz
VGS = 0V, VDS = 25V, f = 1MHz
VGS = 0V, VDS = 25V, f = 1MHz
VDD = 350V, ID = 25mA
VDD = 350V, ID = 25mA
VDD = 350V, ID = 25mA
VDD = 350V, ID = 25mA
TJ = 25°C
TJ = 25°C
Min. Typ. Max. Unit
650
100
3.5 4.5
5.0 6.0
8.0 10.0
14.0 19.0
315
550
250
162
47
38
25
18
9.0
17.0
10.0
3.8
11.2
20.0
12.0
9.5
34
15
4
19
28.2
55.0
30.0
33.0
32
25
10
42
V
µA
Ω
pF
pF
pF
ns
ns
ns
ns
10.5 12.0 13.5
6.35 7.06 7.77
13.2 15.0 16.8
7.5 8.2
µs
µs
µs
µs
© 2006 Fairchild Semiconductor Corporation
FSQ0365, FSQ0265, FSQ0165, FSQ321, FSQ311 Rev. 1.0.5
6
www.fairchildsemi.com
Free Datasheet http://www.Datasheet4U.com

6 Page









Q0165R pdf, datenblatt
Functional Description
1. Startup: At startup, an internal high-voltage current
source supplies the internal bias and charges the
external capacitor (Ca) connected to the Vcc pin, as
illustrated in Figure 20. When VCC reaches 12V, the FPS
begins switching and the internal high-voltage current
source is disabled. The FPS continues its normal
switching operation and the power is supplied from the
auxiliary transformer winding unless VCC goes below the
stop voltage of 8V.
VDC
Ca
VCC
2
5 Vstr
8V/12V
FSQ0365RN Rev.00
VCC good
ICH
Vref
Internal
Bias
Figure 20. Start-up Circuit
2. Feedback Control: FPS employs current mode
control, as shown in Figure 21. An opto-coupler (such as
the FOD817A) and shunt regulator (such as the KA431)
are typically used to implement the feedback network.
Comparing the feedback voltage with the voltage across
the RSENSE resistor makes it possible to control the
switching duty cycle. When the reference pin voltage of
the shunt regulator exceeds the internal reference
voltage of 2.5V, the opto-coupler LED current increases,
thus pulling down the feedback voltage and reducing the
duty cycle. This event typically happens when the input
voltage is increased or the output load is decreased.
2.2 Leading Edge Blanking (LEB): At the instant the
internal SenseFET is turned on, a high-current spike
usually occurs through the SenseFET, caused by
primary-side capacitance and secondary-side rectifier
reverse recovery. Excessive voltage across the Rsense
resistor would lead to incorrect feedback operation in the
current mode PWM control. To counter this effect, the
FPS employs a leading edge blanking (LEB) circuit. This
circuit inhibits the PWM comparator for a short time
(tLEB) after the SenseFET is turned on.
VCC
Idelay
Vref
IFB
VO
VFB
3
OSC
FOD817A
D1 D2
CB 3R
KA431
+
VFB* R
-
SenseFET
Gate
driver
FSQ0365RN Rev. 00
VSD
OLP
Rsense
Figure 21. Pulse-Width-Modulation (PWM) Circuit
3. Synchronization: The FSQ-series employs a valley
switching technique to minimize the switching noise and
loss. The basic waveforms of the valley switching
converter are shown in Figure 22. To minimize the
MOSFET's switching loss, the MOSFET should be
turned on when the drain voltage reaches its minimum
value, as shown in Figure 22. The minimum drain
voltage is indirectly detected by monitoring the VCC
winding voltage, as shown in Figure 22.
Vds
VDC
VRO
VRO
Vsync
tF
Vovp (6V)
2.1 Pulse-by-Pulse Current Limit: Because current
mode control is employed, the peak current through the
SenseFET is limited by the inverting input of PWM
comparator (VFB*), as shown in Figure 21. Assuming
that the 0.9mA current source flows only through the
internal resistor (3R + R = 2.8k), the cathode voltage of
diode D2 is about 2.5V. Since D1 is blocked when the
feedback voltage (VFB) exceeds 2.5V, the maximum
voltage of the cathode of D2 is clamped at this voltage,
thus clamping VFB*. Therefore, the peak value of the
current through the SenseFET is limited.
0.7V
MOSFET Gate
0.2V
300ns Delay
ON ON
FSQ0365RN Rev.00
Figure 22. Valley Resonant Switching Waveforms
© 2006 Fairchild Semiconductor Corporation
FSQ0365, FSQ0265, FSQ0165, FSQ321, FSQ311 Rev. 1.0.5
12
www.fairchildsemi.com
Free Datasheet http://www.Datasheet4U.com

12 Page





SeitenGesamt 24 Seiten
PDF Download[ Q0165R Schematic.PDF ]

Link teilen




Besondere Datenblatt

TeilenummerBeschreibungHersteller
Q0165RFSQ0165RFairchild Semiconductor
Fairchild Semiconductor

TeilenummerBeschreibungHersteller
CD40175BC

Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.

Fairchild Semiconductor
Fairchild Semiconductor
KTD1146

EPITAXIAL PLANAR NPN TRANSISTOR.

KEC
KEC


www.Datenblatt-PDF.com       |      2020       |      Kontakt     |      Suche