ncp5424a ON Semiconductor, ncp5424a Datasheet
ncp5424a
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ncp5424a Summary of contents
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... The NCP5424A can also be configured as two independent out−of−phase controllers. Using the NCP5424A in a current sharing input configuration is ideal for applications where more power is required than is available from one supply, such as video cards or other plug− ...
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... Figure 1. Two−Phase Buck Regulator Application, with Input Current Sharing NCP5424A C11 1 BST CC GATE(H)1 GATE(H)2 Q2 GATE(L)1 GATE(L)2 MTD90N02 IS+1 IS+2 NCP5424A C14 IS− V 0.1 F FB+2 COMP1 COMP2 V V FB1 FB−2 R GND OSC R12 30 http://onsemi.com 2 3 C17 ...
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... GATE(L)2 Low−Side FET Driver for , Channel GND IS+1, IS+2 Positive Current Sense for Channel IS− Negative Current Sense for Channels 1 and 2 NCP5424A Rating Junction−to−Case Junction−to−Ambient Reflow: (SMD styles only) (Note 1) Pin Name V MAX ...
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... Fall Time GATE(H) to GATE(L) Delay GATE(L) to GATE(H) Delay GATE(H)1(2) and GATE(L)1(2) pull−down. PWM Comparator PWM Comparator Offset Artificial Ramp Minimum Pulse Width 2. Guaranteed by design, not 100% tested in production. NCP5424A (0 C < T < < T < 125 OSC = C = 1.0 nF, V ...
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... OVC Comparator Offset Voltage IS Bias Current OVC Common Mode Range OVC Latch COMP2 Discharge Current Discharge Threshold IS− Bias Current OVC Latch COMP1 Discharge Current 3. Guaranteed by design, not 100% tested in production. NCP5424A (0 C < T < < T < 125 1.0 nF 1.0 V ...
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... Oscillator frequency pin. A resistor from this pin to ground sets the oscillator frequency. OSC 14 V Input Power supply pin GATE(L)2 Low Side Synchronous FET driver pin for channel 2. 16 GATE(H)2 High Side Switch FET driver pin for channel 2. NCP5424A FUNCTION http://onsemi.com 6 ...
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... V CC 8.6 V 7.8 V IS+1 IS− IS Set Dominant R 0. 1.0 V NCP5424A OSC BIAS CURRENT SOURCE GEN CLK1 OSC CLK2 PWM Comparator 1 FAULT RAMP1 0.40 V PWM Comparator 2 RAMP2 E/A OFF E/A OFF 0.40 V E/A1 V COMP1 V V FB1 FB−2 FB+2 Figure 2. Block Diagram http://onsemi.com 7 RAMP2 RAMP1 ...
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... THEORY OF OPERATION The NCP5424A is a dual output or single two−phase power supply controller that utilizes the V 2 Two synchronous V buck regulators can be built using a single controller or a single output converter that draws programmable amounts of current from two input voltages. The fixed−frequency architecture, driven from a common ...
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... Compensation Capacitor above the 0.45 V soft start threshold, such that the controller starts switching without a soft start delay. The effect of this is to eliminate the NCP5424A buildup of negative currents that arise during a long start interval where the bottom FET of controller 2 is on. For applications where there are two outputs, this problem can not occur ...
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... If the response of the output filter is faster than the response of the error amplifier, an undesirable positive overshoot can occur in the output. This phenomenon is not unique to the NCP5424A, but is more pronounced because the response of the error amplifier with a large compensation capacitor is intentionally slow. This ...
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... Duty Cycle + LFET * V HFET * V L where buck regulator output voltage; OUT V = high side FET voltage drop due to R HFET NCP5424A V = output inductor voltage drop due to inductor wire L DC resistance buck regulator input voltage low side FET voltage drop due to R ...
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... I = inductor peak current; L(PEAK load current; OUT I = inductor ripple current. L NCP5424A where: I L(VALLEY) Selection of the Output Capacitors These components must be selected and placed carefully to yield optimal results. Capacitors should be chosen to I SW(MAX) provide acceptable ripple on the regulator output voltage. Key specifications for output capacitors are their ESR (Equivalent Series Resistance), and ESL (Equivalent Series Inductance) ...
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... where input inductor input capacitor(s). NCP5424A SELECTION OF THE POWER FET FET Basics The use of a MOSFET as a power switch is compelled by two reasons: 1) high input impedance; and 2) fast switching times. The electrical characteristics of a MOSFET are considered to be nearly those of a perfect switch. Control and drive circuitry power is therefore reduced ...
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... GATE(L)−to−GA TE(H) P LFET(TOTAL RMS( SWL = Synchronous (lower) FET total losses; = Switch Conduction Losses; R QJA ] = total synchronous (lower) FET losses; , and the NCP5424A operating frequency. The ) P GATE(L GATE(H GATE(L)2 = control IC power dissipation; = upper MOSFET gate driver (IC) losses; = lower MOSFET gate driver (IC) losses BST = upper MOSFET gate driver (IC) losses ...
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... Fortunately, the input offset of the NCP5424A is low so that this error term is reduced. Current Sharing Compensation Capacitor Selection The NCP5424A is designed for single and dual output applications. Therefore the IC needs two separate compensation capacitors for the dual output designs, which is not desirable for a single output design. With two compensation capacitors, a race condition between the master and slave controllers is created. During start− ...
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... Chosen value, 0.1 mF will make R a reasonable C RC value. And the IS− divider value can be selected with this equation. V out · out * V os NCP5424A where Output regulated voltage. out V = Offset voltage, example above was 20 mV Chosen value good choice. ...
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... In applications where the internal slope compensation is insufficient, the performance of the NCP5424A−based regulator can be improved through the addition of a fixed amount of external slope compensation at the output of the PWM Error Amplifier (the COMP pin) during the regulator off− ...
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... LAYOUT GUIDELINES When laying out the CPU buck regulator on a printed circuit board, the following checklist should be used to ensure proper operation of the NCP5424A. 1. Rapid changes in voltage across parasitic capacitors and abrupt changes in current in parasitic inductors are major concerns for a good layout. ...
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... G K −T− SEATING PLANE 0.25 (0.010 NCP5424A PACKAGE DIMENSIONS SO−16 D SUFFIX CASE 751B−05 ISSUE J −B− 0.25 (0.010 http://onsemi.com 19 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. ...
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... N. American Technical Support: 800−282−9855 Toll Free USA/Canada NCP5424A JAPAN: ON Semiconductor, Japan Customer Focus Center 2−9−1 Kamimeguro, Meguro−ku, Tokyo, Japan 153−0051 Phone: 81−3−5773−3850 ON Semiconductor Website: http://onsemi.com For additional information, please contact your local Sales Representative. http://onsemi.com 20 NCP5424A/D ...