DataSheet.es    


PDF UC2845A Data sheet ( Hoja de datos )

Número de pieza UC2845A
Descripción (UC2842A - UC2845A) HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
Fabricantes ST Microelectronics 
Logotipo ST Microelectronics Logotipo



Hay una vista previa y un enlace de descarga de UC2845A (archivo pdf) en la parte inferior de esta página.


Total 16 Páginas

No Preview Available ! UC2845A Hoja de datos, Descripción, Manual

UC284XA
UC384XA
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
NOT FOR NEW DESIGN
1 FEATURES
Figure 1. Package
TRIMMED OSCILLATOR DISCHARGE
CURRENT
CURRENT MODE OPERATION TO 500kHz
AUTOMATIC FEED FORWARD
COMPENSATION
DIP-8
SO-8
LATCHING PWM FOR CYCLE-BY-CYCLE
CURRENT LIMITING
Table 1. Order Codes
INTERNALLY TRIMMED REFERENCE WITH
Part Number
Package
UNDERVOLTAGE LOCKOUT
HIGH CURRENT TOTEM POLE OUTPUT
t(s)UNDERVOLTAGE LOCKOUT WITH
HYSTERESIS
cLOW START-UP CURRENT (< 0.5mA)
uDOUBLE PULSE SUPPRESSION
rod2 DESCRIPTION
PThe UC384xA family of control ICs provides the
necessary features to implement off-line or DC to
teDC fixed frequency current mode control schemes
lewith a minimal external parts count. Internally im-
oplemented circuits include a trimmed oscillator for
sprecise DUTY CYCLE CONTROL under voltage
blockout featuring start-up current less than 0.5mA,
Oa precision reference trimmed for accuracy at the
-error amp input, logic to insure latched operation,
)a PWM comparator which also provides current
t(slimit control, and a totem pole output stage de-
csigned to source or sink high peak current. The
uoutput stage, suitable for driving N-Channel MOS-
dFETs, is low in the off-state.
UC2842AD1; UC3842AD1;
UC2843AD1; UC3843AD1;
UC2844AD1; UC3844AD1;
UC2845AD1; UC3845AD1
UC2842AN; UC3842AN;
UC2843AN; UC3843AN;
UC2844AN; UC3844AN;
UC2845AN; UC3845AN
SO-8
DIP-8
Differences between members of this family are
the under-voltage lockout thresholds and maxi-
mum duty cycle ranges. The UC3842A and
UC3844A have UVLO thresholds of 16V (on) and
10V (off), ideally suited off-line applications The
corresponding thresholds for the UC3843A and
UC3845A are 8.5 V and 7.9V. The UC3842A and
UC3843A can operate to duty cycles approaching
100%. A range of the zero to < 50 % is obtained by
the UC3844A and UC3845A by the addition of an
internal toggle flip flop which blanks the output off
every other clock cycle.
ProFigure 2. Block Diagram (toggle flip flop used only in UC3844A and UC3845A)
te 7
Vi
le 5
Obso GROUND
34V
UVLO
2.50V
S/R
5V
REF
VREF GOOD
INTERNAL
BIAS
8 VREF
5V 50mA
LOGIC
6
OUTPUT
4
RT/CT
OSC
T
VFB
COMP
CURRENT
SENSE
2
1
3
ERROR AMP.
+
-
2R
R
S
R
1V
CURRENT
SENSE
COMPARATOR
PWM
LATCH
D95IN331
May 2004
REV. 5
1/16

1 page




UC2845A pdf
UC384XA - UC284XA
Figure 4. Open Loop Test Circuit.
4.7K
ERROR AMP.
ADJUST
4.7K
2N2222
100K
1K
ISENSE
ADJUST
5K
RT
COMP
VFB
ISENSE
RT/CT
VREF
8
1
2
3
4
0.1µF
7
Vi
0.1µF
OUTPUT
6
GROUND
5
A
1W
1K
VREF
Vi
OUTPUT
D95IN343
CT
GROUND
High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and
)bypass capacitors should be connected close to pin 5 in a single point ground. The transistor and 5 K
t(spotentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3.
cFigure 5. Oscillator Frequency vs Timing
uResistance
rodfo
(Hz)
D96IN362
te P1M
bsole100K
CT=470pF
1nF
2.2nF
4.7nF
Figure 7. Oscillator Discharge Current vs.
Temperature.
Idischg
(mA)
8.5
D95IN335
Vi=15V
VOSC=2V
8.0
) - O10K 7.5
ct(s1K
u300
1K 3K 10K 30K RT()
rodFigure 6. Maximum Duty Cycle vs Timing
PResistor
tefo
(Hz)
D96IN363
Obsole80
7.0
-55 -25 0 25 50 75 100 TA(˚C)
Figure 8. Error Amp Open-Loop Gain and
Phase vs. Frequency.
(dB)
D95IN337 φ
Vi=15V
80 VO=2V to 4V 30
Gain
RL=100K
TA=25˚C
60 60
60
40 90
Phase
40
20 120
20 0 150
0
300
1K 3K 10K 30K RT()
-20 180
10 100 1K 10K 100K 1M f(Hz)
5/16

5 Page





UC2845A arduino
UC384XA - UC284XA
Figure 25. External Duty Cycle Clamp and Multi Unit Synchronization.
VREF
8
RA R
8
RB 5K
6
+
5
-
5K
4
R
Q
3
7
BIAS
R
4
OSC
+
+
2
-
C 5K
S
+
2
-
EA
2R
R
1 NE555
ct(s)1.44
f=
u(RA + 2RB)C
Dmax =
RB
RA + 2RB
ProdFigure 26. Soft-Start Circuit
1
5
TO ADDITIONAL
UCX84XAs
D95IN353
bsolete8
duct(s) - O4
Obsolete Pro1M
2
1
R
BIAS
R
OSC
+
+
-
EA
1mA
2R
R
5Vref
+
-
+
1V -
S
Q
R
C5
D95IN354
11/16

11 Page







PáginasTotal 16 Páginas
PDF Descargar[ Datasheet UC2845A.PDF ]




Hoja de datos destacado

Número de piezaDescripciónFabricantes
UC2845Current Mode PWM Controller (Rev. C)Texas Instruments
Texas Instruments
UC2845(UC2844 / UC2845) High Performance Current Mode ControllersON Semiconductor
ON Semiconductor
UC2845HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERSUnisonic Technologies
Unisonic Technologies
UC2845A(UC2842A - UC2845A) HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERST Microelectronics
ST Microelectronics

Número de piezaDescripciónFabricantes
SLA6805M

High Voltage 3 phase Motor Driver IC.

Sanken
Sanken
SDC1742

12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.

Analog Devices
Analog Devices


DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares,
permitiéndote verlos en linea o descargarlos en PDF.


DataSheet.es    |   2020   |  Privacy Policy  |  Contacto  |  Buscar