Datenblatt-pdf.com


KA7526 Schematic ( PDF Datasheet ) - Fairchild

Teilenummer KA7526
Beschreibung Power Factor Correction Controller
Hersteller Fairchild
Logo Fairchild Logo 




Gesamt 22 Seiten
KA7526 Datasheet, Funktion
KA7526
Power Factor Correction Controller
www.fairchildsemi.com
Features
• Internal Startup Timer
• Internal R/C filter which eliminates the Need for an
External R/C filter
• Overvoltage Comparator eliminates Runaway Output
Voltage
• Zero Current Detector
• One Quadrant Multiplier
• Trimmed 1.5% Internal Bandgap Reference
• Under Voltage Lock Out with 5V of Hysteresis
• Totem Pole Output with High State Clamp
• Low Startup and Operating Current
• 8-Pin DIP or 8-Pin SOP
Applications
• Electronic Ballast
• SMPS
Descriptions
The KA7526 provides simple and high performance active
power factor correction. KA7526 is optimized for electronic
ballast and low power, high density power supplies requiring
a minimum board area, reduced component count and low
power dissipation. Addition of internal R/C filter eliminates
the need for an external R/C filter. Internal clamping of the
error amplifier and multiplier outputs improves turn on over-
shoot characteristics and current limiting. Special circuitry
has also been added to prevent no load runaway conditions.
The output drive clamping circuit limits overshoot of the
power MOSFET gate drive Independent of supply voltage,
so that it greatly enhance the system reliability.
8-DIP
8-SOP
1
1
©2000 Fairchild Semiconductor International
Rev. 5.0






KA7526 Datasheet, Funktion
KA7526
Electrical Characteristics (Continued)
Parameter
CURRENT SENSE SECTION
Input Offset Voltage (Note2)
Input Bias Current
Current Sense Delay to Output (Note2)
DETECT SECTION
Detect Input Threshold
Detect Hysteresis
Input Low Clamp Voltage
Input High Clamp Voltage
Input Bias Current
Input High/low Clamp Diode Current (Note2)
OUTPUT DRIVER SECTION
Output Voltage High
Output Voltage Low
Rising Time (Note2)
Falling Time (Note2)
Maximum Output Voltage
Output Voltage With Uvlo Activated
RESTART TIMER SECTION
Restart Time Delay
OVERVOLTAGE PROTECTION SECTION
Symbol
Vio(cs)
Ib(cs)
td(cs)
Vth(det)
HY(det)
Vclamp(I)
Vclamp(h)
Ib(det)
Iclamp
VOH
VOL
tr
tf
Vomax(o)
Vomin(o)
td(rst)
Voltage Feedback Input Threshold
Vth(ovp)
Condition
Vm1=0V, Vm2=2.2V
0VVCC1.7V
-
Vdet Increasing
-
Idet=-100µA
Idet=3mA
1VVdet6V
-
IO=-10mA, VCC=12V
IO=10mA, VCC=12V
CI=1nF
CI=1nF
VCC=20V
VCC=5V, IO=100µA
Vm1=1V, Vm2=3.5V
Vcs=-0.5V, Vm1=1V
Vdet=0V
Min. Typ. Max. Unit
-10 3 10 mV
-1 -0.3 1 µA
- 200 500 ns
1.5 1.8 2.1 V
180 240 400 mV
0.45 0.75 1 V
6.7 7.5 8.3 V
-1 -0.2 1 µA
- - ± 3 mA
8.5 9
-V
- 0.8 1 V
- 130 200 ns
- 50 120 ns
12 13 15 V
- - 1V
- 300 - µs
1.7 1.8 1.9 V
Notes :
1. Because the reference is not brought out externally, this specification cannot be tested on the package part. It is guaranteed
by design.
2. This parameter, although guaranteed, is not tested in production.
3. K = Pin4 Threshold
Vm1×(Vm2-Vref)
(Vm1=Vpin3, Vm2=Vpin2)
6

6 Page









KA7526 pdf, datenblatt
KA7526
Current Sense
Comparator
-
+
CS
4
+
1.65V
Vref
3
MULT
Vm1
Vmo
Error Amp.
- Vm2 +
++ -
2
EA OUT
Fig.3.1 Multiplier Block
1
INV
Current Sense Comparator
The current sense comparator adopt the RS latch configuration to ensure that only a single pulse appears at the drive output
during a given cycle. MOSFET drain current is converted to voltage using an external sense resistor in series with the external
power MOSFET. When sense voltage exceeds the threshold set by the multiplier output, the current sense comparator termi-
nates the gate drive to the MOSFET and resets the PWM latch. The latch insures that the output remains in a low state after the
MOSFET drain current falls back to zero.
The peak inductor current under normal operating conditions is controlled by the multiplier output, Vmo.
Abnormal operating conditions occur during preconverter start-up at extremely high line or as output voltage sensing is lost.
Under these conditions, the multiplier output and current sense threshold will be internally clamped to 1.65V. Therefore, the
maximum peak switch current is limited to:
Ipk(max) = 1.65V / Rsense
An internal R/C filter has been included to attenuate any high frequency noise that may be present on the current waveform.
This circuit block eliminates the need for an external R/C filter otherwise required for proper operation of the circuit.
+
-
1.65V
cs
4
Rsense
Multiplier
Output
External R/C Filter
can be eliminated
Fig. 4.1 Current Sense Circuit
12

12 Page





SeitenGesamt 22 Seiten
PDF Download[ KA7526 Schematic.PDF ]

Link teilen




Besondere Datenblatt

TeilenummerBeschreibungHersteller
KA7521ELECTRONIC BALLAST CONTROLLERFairchild Semiconductor
Fairchild Semiconductor
KA7522DIMMING BALLAST CONTROL ICFairchild Semiconductor
Fairchild Semiconductor
KA7522DDIMMING BALLAST CONTROL ICFairchild Semiconductor
Fairchild Semiconductor
KA7524POWER FACTOR CONTROLLERUnisonic Technologies
Unisonic Technologies
KA7524POWER FACTOR CONTROLLERContek
Contek

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