ISL6721 Intersil Corporation, ISL6721 Datasheet
ISL6721
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ISL6721 Summary of contents
Page 1
... Data Sheet Flexible Single Ended Current Mode PWM Controller The ISL6721 is a low power, single-ended pulse width modulating (PWM) current mode controller designed for a wide range of DC-DC conversion applications including boost, flyback, and isolated output configurations. Peak current mode control effectively handles power transients and provides inherent over-current protection ...
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... ERROR 2.5V AMPLIFIER + - VFB VREF 20K 3.0V 12K 1.5V ON 30K OSCILLATOR COMPARATOR - RTCT + 1mA VREF 100 SYNC 4.5K 2 ISL6721 V REF 5. CHARGE VOLTAGE CLAMP SS CHARGED OC DETECT OVERCURRENT Q COMPARATOR Q 50 µS RETRIGGERABLE ONE SHOT PWM COMPARATOR + - UV COMPARATOR START 1/3 100nS BLANKING S Q Bi-Directional Synchronization R Q OSC IN ...
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... Typical Application - 48V Input Dual Output Flyback, 3.3V @ 2.5A, 1.8V @ 1.0A VIN 36-75V C1 R2 VIN- SYNC VR1 3 ISL6721 C18 R24 C2 C5 CR6 C3 TP1 R22 R23 R25 TP3 TP5 D2 R8 R10 R11 R9 SP1 SP2 CR5 T1 ISO LATIO N C21 ...
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... Human Body Model (Per MIL-STD-883 Method 3015. .1250V Operating Conditions Temperature Range ISL6721Ax . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40 Supply Voltage Range (Typical 9-18 VDC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied ...
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... Comparator High Threshold - with External SYNCH Comparator Low Threshold Discharge Current SYNCHRONIZATION Input High Threshold Input Pulse Width Input Frequency Range Input Impedance VOH VOL SYNCH Advance Output Pulse Width 5 ISL6721 = V < 20V ±10 11kΩ 330 pF (Continued) A TEST CONDITIONS (Note 5) (Note 5) o ...
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... OVER CURRENT PROTECTION Minimum ISET Voltage Maximum ISET Voltage Restart Delay OV & UV VOLTAGE MONITOR Over Voltage Threshold Under Voltage Fault Threshold Under Voltage Clear Threshold Under Voltage Hysteresis Voltage 6 ISL6721 = V < 20V ±10 11kΩ 330 pF (Continued) A TEST CONDITIONS Sustained OC Threshold < ...
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... Temperature (C) o TEMPERATURE FIGURE 3. OSCILLATOR FREQUENCY vs TEMPERATURE 7 ISL6721 = V < 20V ±10 11kΩ 330 pF (Continued) A TEST CONDITIONS (Note 5) (Note 5) (Note 5) 80 110 80 110 o C FIGURE 2. VREF REFERENCE VOLTAGE vs TEMPERATURE ...
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... PWM comparator. The control loop frequency compensation network is connected between the COMP and FB pins. The ISL6721 features a built-in full cycle soft start. Soft start is implemented as a clamp on the maximum COMP voltage Feedback voltage input connected to the inverting input of the error amplifier. The non-inverting input of the error amplifier is internally tied to a reference voltage ...
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... Functional Description Features The ISL6721 current mode PWMs make an ideal choice for low-cost flyback and forward topology applications requiring enhanced control and supervisory capability. With adjustable over and under voltage thresholds, over current threshold, and hic-cup delay, a highly flexible design with minimal external components is possible ...
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... CC is attempted. If the fault is cleared, a soft start cycle begins. 10 ISL6721 Otherwise another shutdown cycle occurs condition also results in a shutdown fault, but the device does not enter the low power mode and no restart delay occurs when the fault clears ...
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... PGND ground plane. Reference Design The Typical Application Schematic features the ISL6721 in a conventional dual output 10W discontinuous mode flyback DC-DC converter. The ISL6721EVAL1 demonstration unit implements this design and is available for evaluation. ...
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... It has more than the L required air gap volume to store the energy required, but was needed for the window area it provides. Aeff = 31 • ISL6721 lg = 1.56 • 10 The flux density ∆B is only 0.069T or 690 gauss, a relatively (EQ. 9) low value. Since µH µ • ...
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... Pcond Rdson Iprms W 13 ISL6721 where Rdson is the ON resistance of the MOSFET and Iprms is the RMS primary current. Determining the conduction losses is complicated by the variation of Rdson with temperature. As junction temperature increases, so does Rdson, which increases losses and raises the junction temperature more, and so on possible for the device to enter a thermal runaway situation without proper heatsinking ...
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... Control Loop Design The major components of the feedback control loop are a programmable shunt regulator, an opto-coupler, and the inverting amplifier of the ISL6721. The opto-coupler is used to transfer the error signal across the isolation barrier. The opto-coupler offers a convenient means to cross the isolation barrier, but it adds complexity to the feedback control loop ...
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... ISET threshold. ISET was set at 1.0V, near its maximum, to minimize noise effects. When 15 ISL6721 determining ISET, the internal gain and offset of the ISENSE signal in the control IC must be taken into account. The maximum peak primary current was determined earlier ...
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... Using this technique to determine the compensation, the following values for the EA components were selected. R17 = R18 = R15 = 1kΩ R20 = open C13 = 100nF C14 = 100pF 16 ISL6721 A Bode plot of the closed loop system at low line, max load appears below. (EQ. 28) • (EQ. 29) (EQ ...
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... OC fault function is enabled. The OC condition is detected and the soft start capacitor is 17 ISL6721 discharged to the 4.375V OC fault threshold at which point the IC enters the fault shutdown mode. Trace 2 shows the = 48V ...
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... Resistor, 0603 Resistor, 0603, 1% 165 Resistor, 0603, 1% 10.0 Resistor, 1206, 1% 5.11 Resistor, 0603, 1% 3.92K Resistor, 2512, 1% 100 Resistor, 0603, 1% 1.00 Resistor, 2512, 1% 221K Resistor, 0603, 1% 75.0K Resistor, 0603, 1% OMIT Transformer, MIDCOM 31555 Opto-coupler, NEC PS2801-1 Shunt Reference, National LM431BIM3 PWM, Intersil ISL6721IB Zener, 15V, Zetex BZX84C15 ...
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... Minimum space between protrusion and adjacent lead is 0.07mm (0.0027 inch). 10. Controlling dimension: MILLIMETER. Converted inch dimen- sions are not necessarily exact. (Angles in degrees) 19 ISL6721 M16.173 16 LEAD THIN SHRINK SMALL OUTLINE PLASTIC PACKAGE ...
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... However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 20 ISL6721 M16.15 (JEDEC MS-012-AC ISSUE C) 16 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE ...