PDF CS52843EDR8 Data sheet ( Hoja de datos )

Número de pieza	CS52843EDR8
Descripción	Current Mode PWM Control Circuit
Fabricantes	Cherry Semiconductor Corporation
Logotipo
Hay una vista previa y un enlace de descarga de CS52843EDR8 (archivo pdf) en la parte inferior de esta página. Total 6 Páginas
No Preview Available ! CS52843 Current Mode PWM Control Circuit Description The CS52843 provides all the nec- essary features to implement off- line fixed frequency current-mode control with a minimum number of external components. The CS52843 incorporates a new precision temperature-controlled oscillator to minimize variations in frequency. An undervoltage lock- out ensures that VREF is stabilized before the output stage is enabled. In the CS52843 turn on is at 8.4V and turn off at 7.6V. Other features include low start-up current, pulse-by-pulse current lim- iting, and a high-current totem pole output for driving capacitive loads, such as gate of a power MOSFET. The output is low in the off state, consistent with N-channel devices. Absolute Maximum Ratings Supply Voltage (ICC<30mA) ..........................................................Self Limiting Supply Voltage (Low Impedance Source)...................................................30V Output Current ...............................................................................................±1A Output Energy (Capacitive Load) .................................................................5µJ Analog Inputs (VFB, VSENSE)...........................................................-0.3V to 5.5V Error Amp Output Sink Current...............................................................10mA Lead Temperature Soldering Reflow (SMD styles only) ...........60 sec. max above 183°C, 230°C peak Block Diagram VCC VCC Undervoltage Lock-out 34V Gnd VFB COMP OSC Sense 8.4V/7.6V Set/ 5.0 Volt Reset Reference Error Amplifier - + 2.50V OUTPUT R ENABLE R Oscillator 2R R S R 1V Current PWM Sensing Latch Comparator NOR Internal Bias VCC Pwr VREF VOUT Pwr Gnd Features s Optimized for Off-line Control s Internally Temperature Compensated Oscillator s VREF Stabilized before Output Stage is Enabled s Very Low Start-up Current 300 µA (typ) s Pulse-by-pulse Current Limiting s Improved Undervoltage Lockout s Double Pulse Suppression s 2% 5 Volt Reference s High Current Totem Pole Output Package Options 8L SO Narrow COMP 1 VFB 2 8 VREF 7 VCC Sense 3 6 VOUT OSC 4 5 Gnd 14L SO Narrow COMP 1 NC 2 VFB 3 NC 4 Sense 5 NC 6 OSC 7 14 VREF 13 NC 12 VCC 11 VCC Pwr 10 VOUT 9 Pwr Gnd 8 Gnd Rev. 12/23/97 Cherry Semiconductor Corporation 2000 South County Trail, East Greenwich, RI 02818 Tel: (401)885-3600 Fax: (401)885-5786 Email: [email protected] Web Site: www.cherry-semi.com 1 A ® Company 1 page Circuit Description When the power supply sees a sudden large output cur- rent increase, the control voltage will increase allowing the duty cycle to momentarily increase. Since the duty cycle tends to exceed the maximum allowed to prevent trans- former saturation in some power supplies, the internal oscillator waveform provides the maximum duty cycle clamp as programmed by the selection of oscillator timing components. VOSC OSC RESET Toggle F/F Output EA Output Switch Current VCC IO VO Setting the Oscillator The times Tc and Td can be determined as follows: ( )tc = RTCT ln VREF - VLOWER VREF - VUPPER ( )td = RTCT ln VREF - IdRT - VLOWER VREF - IdRT - VUPPER Substituting in typical values for the parameters in the above formulas: VREF = 5.0V, VUPPER = 2.7V, VLOWER = 1.0V, Id = 8.3mA, then tc ≈ 0.5534RTCT ( )td = RTCT ln 2.3 - 0.0083 RT 4.0 - 0.0083 RT Figure 2: Timing Diagram For better accuracy RT should be ≥10kΩ. VREF OSC Gnd RT CT Grounding High peak currents associated with capacitive loads neces- sitate careful grounding techniques. Timing and bypass capacitors should be connected close to Gnd in a single point ground. The transistor and 5kΩ potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to Sense. Vupper Vlower tc td Sawtooth Mode LARGE RT (≈10kΩ) VOSC Triangular Mode SMALL RT (≈700kΩ) Internal Clock VREF Internal Clock Figure 3: Oscillator Timing Network and Parameters 5 5 Page

Páginas	Total 6 Páginas
PDF Descargar	[ Datasheet CS52843EDR8.PDF ]

Hoja de datos destacado

Número de pieza	Descripción	Fabricantes
CS52843EDR14	Current Mode PWM Control Circuit	Cherry Semiconductor Corporation
CS52843EDR8	Current Mode PWM Control Circuit	Cherry Semiconductor Corporation

Número de pieza	Descripción	Fabricantes
SLA6805M	High Voltage 3 phase Motor Driver IC.	Sanken
SDC1742	12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.	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