Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

ISL6843IBZ Datasheet(PDF) 9 Page - Intersil Corporation

Part # ISL6843IBZ
Description  Improved Industry Standard Single-Ended Current Mode PWM Controller
Download  13 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  INTERSIL [Intersil Corporation]
Direct Link  http://www.intersil.com/cda/home
Logo INTERSIL - Intersil Corporation

ISL6843IBZ Datasheet(HTML) 9 Page - Intersil Corporation

Back Button ISL6843IBZ Datasheet HTML 5Page - Intersil Corporation ISL6843IBZ Datasheet HTML 6Page - Intersil Corporation ISL6843IBZ Datasheet HTML 7Page - Intersil Corporation ISL6843IBZ Datasheet HTML 8Page - Intersil Corporation ISL6843IBZ Datasheet HTML 9Page - Intersil Corporation ISL6843IBZ Datasheet HTML 10Page - Intersil Corporation ISL6843IBZ Datasheet HTML 11Page - Intersil Corporation ISL6843IBZ Datasheet HTML 12Page - Intersil Corporation ISL6843IBZ Datasheet HTML 13Page - Intersil Corporation  
Zoom Inzoom in Zoom Outzoom out
 9 / 13 page
background image
9
FN9124.11
February 23, 2012
Pin Descriptions
RTCT -
This is the oscillator timing control pin. The
operational frequency and maximum duty cycle are set by
connecting a resistor, RT, between VREF and this pin and a
timing capacitor, CT, from this pin to GND. The oscillator
produces a sawtooth waveform with a programmable
frequency range up to 2.0MHz. The charge time, tC, the
discharge time, tD, the switching frequency, f, and the
maximum duty cycle, Dmax, can be calculated from
Equations 1, 2, 3 and 4:
Figure 4 may be used as a guideline in selecting the
capacitor and resistor values required for a given frequency.
COMP -
COMP is the output of the error amplifier and the
input of the PWM comparator. The control loop frequency
compensation network is connected between the COMP and
FB pins.
FB -
The output voltage feedback is connected to the
inverting input of the error amplifier through this pin. The
non-inverting input of the error amplifier is internally tied to a
reference voltage.
CS -
This is the current sense input to the PWM comparator.
The range of the input signal is nominally 0V to 1.0V and has
an internal offset of 100mV.
GND -
GND is the power and small signal reference ground
for all functions.
OUT -
This is the drive output to the power switching device.
It is a high current output capable of driving the gate of a
power MOSFET with peak currents of 1.0A.
VDD -
VDD is the power connection for the device. The total
supply current will depend on the load applied to OUT. Total
IDD current is the sum of the operating current and the
average output current. Knowing the operating frequency, f,
and the MOSFET gate charge, Qg, the average output
current can be calculated in Equation 5:
To optimize noise immunity, bypass VDD to GND with a
ceramic capacitor as close to the VDD and GND pins as
possible.
VREF -
The 5.00V reference voltage output. +1.0/-1.5%
tolerance over line, load and operating temperature. Bypass
to GND with a 0.1µF to 3.3µF capacitor to filter this output as
needed.
Functional Description
Features
The ISL684x current mode PWMs make an ideal choice for
low-cost flyback and forward topology applications. With its
greatly improved performance over industry standard parts,
it is the obvious choice for new designs or existing designs
which require updating.
Oscillator
The ISL684x family of controllers have a sawtooth oscillator
with a programmable frequency range to 2MHz, which can
be programmed with a resistor from VREF and a capacitor to
GND on the RTCT pin. (Please refer to Figure 4 for the
resistor and capacitance required for a given frequency.)
Soft-Start Operation
Soft-start must be implemented externally. One method,
illustrated in Figure 5, clamps the voltage on COMP.
Gate Drive
The ISL684x family are capable of sourcing and sinking 1A
peak current. To limit the peak current through the IC, an
optional external resistor may be placed between the
totem-pole output of the IC (OUT pin) and the gate of the
MOSFET. This small series resistor also damps any
oscillations caused by the resonant tank of the parasitic
inductances in the traces of the board and the FET’s input
capacitance.
Slope Compensation
For applications where the maximum duty cycle is less than
50%, slope compensation may be used to improve noise
immunity, particularly at lighter loads. The amount of slope
compensation required for noise immunity is determined
empirically, but is generally about 10% of the full scale
current feedback signal. For applications where the duty
cycle is greater than 50%, slope compensation is required to
prevent instability. The minimum amount of slope
compensation required corresponds to 1/2 the inductor
downslope. Adding excessive slope compensation,
however, results in a control loop that behaves more as a
voltage mode controller than as a current mode controller.
Slope compensation may be added to the CS signal shown
in Figure 7.
tC 0.583 RT CT
(EQ. 1)
tD RT
CT
0.0083 RT 4.3
0.0083 RT 2.4
----------------------------------------------
⎝⎠
⎛⎞
ln
(EQ. 2)
f
1tC tD
+
()
=
(EQ. 3)
DtC f
=
(EQ. 4)
(EQ. 5)
IOUT
Qg f
×
=
FIGURE 5. SOFT-START
VREF
COMP
GND
ISL6840, ISL6841, ISL6842, ISL6843, ISL6844, ISL6845


Similar Part No. - ISL6843IBZ

ManufacturerPart #DatasheetDescription
logo
Intersil Corporation
ISL6843IBZ INTERSIL-ISL6843IBZ Datasheet
278Kb / 12P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
ISL6843IBZ INTERSIL-ISL6843IBZ Datasheet
287Kb / 12P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
ISL6843IBZ INTERSIL-ISL6843IBZ Datasheet
391Kb / 13P
   Improved Industry Standard Single-Ended
ISL6843IBZ INTERSIL-ISL6843IBZ Datasheet
391Kb / 13P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
ISL6843IBZ INTERSIL-ISL6843IBZ Datasheet
372Kb / 14P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
September 29, 2015
More results

Similar Description - ISL6843IBZ

ManufacturerPart #DatasheetDescription
logo
Intersil Corporation
ISL6840 INTERSIL-ISL6840_07 Datasheet
278Kb / 12P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
ISL6840IRZ-T INTERSIL-ISL6840IRZ-T Datasheet
372Kb / 14P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
September 29, 2015
ISL6843CBZ-T INTERSIL-ISL6843CBZ-T Datasheet
391Kb / 13P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
ISL6842 INTERSIL-ISL6842 Datasheet
264Kb / 9P
   Improved Industry Standard Single Ended Current Mode PWM Controller
ISL78215 INTERSIL-ISL78215 Datasheet
231Kb / 11P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
ISL6840 INTERSIL-ISL6840 Datasheet
287Kb / 12P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
logo
Renesas Technology Corp
ISL6840 RENESAS-ISL6840 Datasheet
683Kb / 14P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
logo
Intersil Corporation
ISL6843IUZ-T INTERSIL-ISL6843IUZ-T Datasheet
391Kb / 13P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
ISL6840IUZ-T INTERSIL-ISL6840IUZ-T Datasheet
391Kb / 13P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
February 23, 2012
logo
Renesas Technology Corp
ISL78215 RENESAS-ISL78215 Datasheet
578Kb / 11P
   Improved Industry Standard Single-Ended Current Mode PWM Controller
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com