Senin, 13 Mei 2013

Komponen

Resistor :

Beberapa Unsur, seperti karbon,  menghantar listrik cukup baik tetapi  tidak sungguh baik.
Daya hantar dapat diubah dengan  menambahkan bahan tak murni seperti tanah liat ke pasta karbon, atau dengan lilitan suatu kawat tipis. Komponen elektrik yang dibuat dengan cara ini disebut resistor. Resistor penting dalam sirkit elektronik sebab ia mempertimbangkan kendali arus.

Resistor dapat dibuat dengan karakteristik yang tepat. Resistor dengan daya hantar bagus memiliki nilai tahanan yang kecil sedangkan yang memiliki nilai tahanan besar memiliki daya hantar yang buruk. Ukuran unit resistor disebut Ohm. Kadang-kadang nilai spesifik kabel diukur dalam ohm/foot atau ohm/kilometer.
Biasanya pada sebuah sistem elektrikal dibutuhkan nilai resistansi yang kecil atau nilai Ohm yang rendah. Ini dikarenakan resistor mengubah energi listrik ke energi panas. Kabel tebal/besar dan tegangan tinggi menurunkan resistensi dalam jaringan listrik jarak jauh. Ini alasannya tower tegangan tinggi dengan tegangan yang berbahaya diperlukan dalam sistem jaringan utama.

Berikut ini adalah tabel bagaimana kita membaca nilai suatu resistor.


Sabtu, 04 Mei 2013

Gate Driver ICs

Gate Driver ICs

IC gerbang pengemudi, International Rectifier's MOSFET and IGBT  adalah yang paling sederhana, solusi biaya paling rendah dan paling kecil untuk  mengarahkan  hingga  1200V di dalam aplikasi hingga ke 12kW, dan dapat menghemat 30% pada bagian area PCB 50% lebih kecil jika dibandingkan dengan discrit opto-coupler atau solusi dasar trafo. Dengan penambahan sedikit komponen eksternal, ic-ic gerbang terkemudi IR  menyediakan kemampuan pengarahan penuh dengan cepat mengatur kecepatan, designed unik dan power disipasi yang rendah.

Gerbang pengemudi nya IC, menghasilkan arus dan tegangan untuk mengaktifkan dan menonaktifkan MOSFET dan IGBT dari output DSP microcontroller ata alat logika lainnya.Input 3.3 volt khas untuk level signal logic. Semua IC gerbang pengemudi IR adalah sepadan dengan CMOS yang bisa dipergantikan dengan TTL. Arus output adalah 2 Amp.


Keuntungan IR
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Dead-time rendah hingga 500 nS, respon frequensi hingga 100 kHz
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Menaikkan selang kecepatan dan mengatur kekuatan motor pengemudi.
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Memungkinkan desain gerbang penyearah tidak rata.
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Power disipasi rendah.
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Mirip dengan sistem opto-coupler.
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Komponen lebih sedikit 30% dan PCB lebih kecil  50%.
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Tidak memerlukan power supply tambahan.
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10X lebih cepat delay matching (±50ns)
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Tidak ada penurunan capaian derajat dari waktu kewaktu.
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Waktu cepat untuk signal arus lebih 1.5µs versus 6µs)
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Menekan  EMI dan tegangan kejut.

FEATURES AT A GLANCE
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600V and 1200V gate driver in a single IC for MOSFET and IGBTs
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Multiple Configurations
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Single high side
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Half-bridge
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3 phase inverter driver
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Up to +2.0/-2.0A output source/sink current enables fast switching
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Integrated protection and feedback functions
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Optional deadtime control
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Tolerant to negative voltage transient
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Up to 50V/ns dV/dt immunity
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Optional soft turn-on
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Uses low cost bootstrap power supply                                    
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CMOS and LSTTL input compatible
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APPLICATIONS
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Plasma Display Panels

IR Gate Driver ICs Simplify Design
Driving a MOSFET or IGBT in the high side position of a half-bridge topology or 3 phase inverter leg offers the additional challenge that the gate voltage is referenced to the source rather than to ground. The source voltage is a floating point at up to the maximum bus voltage, or voltage rating of the MOSFET or IGBT, 600V and up for motor drive, lighting or SMPS applications. IR gate driver uses a patented level shifter technology for high voltage application and offers the only 1200V rating in the industry.
These ICs simplify circuit designs by integrating extensive functionality. They use a low cost bootstrap supply, while opto-coupler-based circuits typically require an auxiliary power supply. IR Gate Driver ICs offer optional single input or dual input programmable deadtime control for low side and high side drivers as well as for 3 phase drivers to provide design flexibility and allows to minimize cross-conduction. Unique 3-phase drivers allow driving a 3 phase inverter using a single IC.

IR Gate Driver ICs enable rugged driver designs
IR Gate Driver ICs are specifically designed with motor drive applications in mind. The newest soft-turn-on limits voltage and current spike and reduce EMI. In addition, they have up to 50V/ns dV/dt immunity and are tolerant to negative voltage transient. The under-voltage lock-out available for most drivers prevents shoot-through currents and device failures during power-up and power-down without any additional circuitry. The output drivers feature a high pulse current buffer stage designed for minimum driver cross-conduction.
Noise immunity is important for the high-side position which has a floating voltage and is susceptible to high noise levels, particularly in motor drive applications. Noise immunity ensures that the MOSFET or IGBT doesn't turn on accidentally. Noise immunity is obtained by using Schmitt-triggered input with pull-down. Additional noise immunity is obtained with separate logic and ground pins in some ICs, such as the 600V ICs in 14-pin packages.

IR Gate Driver ICs enable fast switching speeds
IR Gate Drive ICs have ten times better delay matching performance than opto-coupler-based solutions. Delay matching between the low-side and high-side driver is typically within ± 50ns (and as low as ± 10ns for some specialty products), allowing complete dead-time control for better speed range and torque control in motor drive applications. Fast switching also reduces switching power losses and allows leveraging the full benefits of the fastest IGBTs available on the market today for better torque control over a wider speed range.

Application Notes:
AN-978: HV Floating MOS-Gate Driver ICs
AN-985: Six Output 600V MGDs Simplify 3-Phase Motor Drives
Design Notes:
DN500: Short Circuit Protection for Power Inverters
DN501: Accurate Current Sensing in High Voltage Motor Drives
DN502: Short Circuit Protection for Three-Phase Power Inverters
Design Tips:
DT92-2: High Current Buffer for Control ICs
DT04-4: Using Monolithic High Voltage Gate Drivers