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R7711A Dataheets PDF



Part Number R7711A
Manufacturers Richtek
Logo Richtek
Description Primary Feedback CC/CV PWM Controller
Datasheet R7711A DatasheetR7711A Datasheet (PDF)

® R7711A Primary Feedback CC/CV PWM Controller for Flyback Converters General Description Features The R7711A is a current mode PWM controller which includes primary side voltage feedback technology. It controls the output voltage and current accurately without shunt regulator and opto-coupler on secondary side to reduce the part count and save costs. The R7711A is designed especially for low power applications, such as chargers for cell phones, PDAs, and other mobile products. Complete prot.

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® R7711A Primary Feedback CC/CV PWM Controller for Flyback Converters General Description Features The R7711A is a current mode PWM controller which includes primary side voltage feedback technology. It controls the output voltage and current accurately without shunt regulator and opto-coupler on secondary side to reduce the part count and save costs. The R7711A is designed especially for low power applications, such as chargers for cell phones, PDAs, and other mobile products. Complete protections are provided, such as output Under- Voltage Protection, output Over-Voltage Protection, VDD Over-Voltage Protection, Over-Temperature Protection, and Secondary Rectifier Short-circuit Protection. The ultra low start-up current and operating current of the R7711A achieves low power consumption in standby mode. The R7711A supports burst switching green mode operation to meet CEC regulations and Energy-Star requirements.  Programmable Primary-Side CC/CV Regulation  Low No Load Input Power (<30mW at 230VAC)  Burst Switching Green Mode PWM Operation  Low Start-up Current (<10mA)  Easy EMI Solution  Built-in Jittering Frequency  Built-in Soft Gate Driver  Programmable Cable Drop Compensation  Adjustable Propagation Delay Compensation  VDD Over-Voltage Protection (VDDOVP)  Output Over-Voltage Protection (OVP)  Output Under-Voltage Protection (UVP)  Secondary Rectifier Short-Circuit Protection (SRSP)  Internal Over-Temperature Protection (OTP)  RoHS Compliant and Halogen Free Applications  Switching AC/DC Adaptor and Battery Charger  DVD Open Frame Power Supply  STB Power  Cell Phone Charger  Networking Power Supply Simplified Application Circuit L AC Mains (90V to 265V) N VDD DMAG R7711A COMP GATE CS GND 2 Copyright ©2020 Richtek Technology Corporation. All rights reserved. R7711A-08 August 2020 VOUT is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 R7711A Marking Information FN=DNN FN= : Product Code DNN : Date Code Pin Configuration (TOP VIEW) CS COMP DMAG 6 5 4 23 GATE GND VDD SOT-23-6 Ordering Information Part No R7711AGE Status Obsolete Package Type SOT-23-6 The part status values are defined as below : Active : Device is in production and is recommended for new designs. Lifebuy : The device will be discontinued, and a lifetime-buy period is in effect. NRND : Not recommended for new designs. Preview : Device has been announced but is not in production. Obsolete : Richtek has discontinued the production of the device. Functional Pin Description Pin No. 1 2 3 4 5 6 Pin Name GATE GND VDD DMAG COMP CS Pin Function MOSFET gate driver output. Connect this pin to the gate of an external N-channel power MOSFET. Ground of the controller. Power supply input. The controller will be enabled when VDD exceeds VTH_ON and disabled when VDD decreases lower than VTH_OFF. Demagnetization pin. Input and output voltage detection from auxiliary winding. The current (ICABLE) flows into this pin to achieve cable drop compensation function. This pin is also used to detect the signal of the rectified input voltage for propagation delay compensation and minimum on-time control. Feedback compensation pin. This pin is the output of the internal operational transconductance amplifier (OTA) to connect a proper RC network from this pin to GND for feedback loop compensation. Current sensing input. Connect this pin to a current sense resistor used to detect the current of the primary-side winding. Copyright ©2020 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. R7711A-08 August 2020 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 Copyright ©2020 Richtek Technology Corporation. All rights reserved. R7711A-08 August 2020 DMAG VDD SRSP DMAX Detect VOUT UVP VCOMP Clamp Circuit OTP VOUT OVP Timer Oscilltor Shutdown Logic Disable Bias & Bandgap POR UVLO + - VTH_VDDOV + VTH_ON / VTH_OFF CC Control TOFF ICLAMP S/H VSH_DMAG VREF 2.5V -gm + OTA + + X3 LEB SQ R QN Soft Driver Minimum Ton ICLAMP GATE GND COMP CS Functional Block Diagram R7711A R7711A Operation General Description The R7711A is a peak current-mode PWM controller VDRAIN VIN + (VOUT + VDO) × NP NS VIN designed for off-line flyback converter in DCM (Discontinuous Conduction Mode) operation. It can achieve 0V accurate CV (Constant-Voltage) or CC (Constant-Current) output without voltage and current sensing circuits on the secondary side, as shown the Figure 1. When the output VGATE (VOUT VAUX + VDO) TON × NA NS 0V voltage is below the under-voltage threshold (VOUT_MIN), the R7711A works in hiccup mode. VIN× NA NP Knee Point VDMAG VREF VOUT at end of output cable 0V TS IDSPK VOUT_SET IDS IDO TON_D VOUT_MIN CV operation CC operation Hiccup operation Upper Limit Lower Limit PK IDOIOUT t0 t1 t2 t3 t4.


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