Datasheet InnoSwitch-CP (Power Integrations) - 5

InnoSwitch-CP
The most likely event that could require an additional handshake is The mid-point of an external resistor divider network between the when the primary stops switching resulting from a momentary line VOUT and SECONDARY GROUND pins is tied to the FEEDBACK pin drop-out or brown-out event. When the primary resumes operation, to regulate the output voltage. The internal voltage comparator it will default into a start-up condition and attempt to detect hand- reference voltage is V (1.265 V). REF shake pulses from the secondary. The external current sense resistor connected between IS and In the event the secondary does not detect that the primary responds SECONDARY GROUND pins is used to regulate the output current in to requests for 14 consecutive cycles, or if the secondary detects that constant current mode. The internal current sense comparator the primary is switching without cycle requests, the secondary threshold IS is used to determine the value at which the power VTH control er will initiate a second handshake sequence. supply output current is regulated. This protection mode also provides additional protection against
Secondary Controller Oscillator
cross-conduction of the SR MOSFET while the primary is switching. The typical oscillator frequency is internal y set to an average This protection mode also prevents output overvoltage in the event frequency of 100 kHz. the primary is reset while the secondary is still in control and light/ medium load conditions exist. The oscillator incorporates circuitry that introduces a small amount of frequency jitter, typical y 6 kHz peak-to-peak, to minimize EMI
Line Voltage Monitor
emission. The modulation rate of the frequency jitter is set to 1 kHz The VOLTAGE MONITOR pin is used for input under and overvoltage to optimize EMI reduction for both average and quasi-peak emissions. sensing and protection function.
Output Overvoltage Protection
A 8 MW resistor is tied between the high voltage bulk DC capacitor In the event the sensed voltage on the FEEDBACK pin is 2% higher after the bridge or connected through a set of diodes from the AC than the regulation threshold, a bleed current of ~2.5 mA is applied side of bridge and small high-voltage capacitor and bleed resistor on the VOUT pin. This bleed current increases to ~140 mA in the (for fast AC reset) and VOLTAGE MONITOR pin to enable this function. event the FEEDBACK pin voltage is raised to beyond ~20% of the To disable this function the VOLTAGE MONITOR pin should be tied to internal FEEDBACK pin reference voltage. The current sink on the the PRIMARY BYPASS pin. VOUT pin is intended to discharge the output voltage for momentary overshoot events. The secondary does not relinquish control to the At power-up after the BPP is charged and the I is latched, prior to LIM primary during this mode of operation. switching the state of VOLTAGE MONITOR pin current is checked to determine that it is above brown-in (I ) And below the overvoltage
FEEDBACK Pin Short Detection
UV+ shutdown threshold (I ) To proceed with start-up. In the event the FEEDBACK pin voltage is below the V threshold OV+ FB(OFF) at start-up, the secondary will complete the primary/secondary hand- If during normal operation the VOLTAGE MONITOR pin current fal s shake and will stop requesting pulses to initiate an auto-restart. The below the brown-out (I ) threshold and remains below brown-out UV- secondary will stop requesting cycles for t , to begin primary-side (I ) for longer than t the control er enters into auto-restart with a AR(SK) UV- UV- auto-restart of t . In this condition, the total apparent AR off- time short auto-restart off-time (~200 ms). Switching will only resume AR(OFF)SH is t + t . During normal operation, the secondary will stop once the VOLTAGE MONITOR pin current is above the brown-in AR(SK) AR(OFF)SH requesting pulses from the primary to initiate an auto-restart cycle when threshold (I ) for a time period exceeding ~150 ms. UV+ the FEEDBACK pin voltage fal s below V threshold. The deglitch FB(OFF) In the event during normal operation the VOLTAGE MONITOR pin filter on the V is less than 10 msec. FB(OFF) current is above the overvoltage threshold (I ) for longer than t , OV+ OV
Cable Drop Compensation (CDC)
the control er will enter auto-restart with a short auto-restart off-time The amount of cable drop compensation is a function of the load with (~200 ms). Switching will only resume once the VOLTAGE MONITOR respect to the constant current regulation threshold as il ustrated in pin current fall below (I ) for a time period exceeding ~150 ms. OV- Figure 8 when used with CHY103 or any current source feedback. It
Secondary Controller
is 6% of V if adjusted by changing feedback divider like CHY100/101. OUT Once the device enters the short auto-restart OFF-time, the PRIMARY BYPASS pin will activate an internal bleed to discharge the input bulk capacitor. The feedback driver block is the drive to the FluxLink communication loop transferring switching pulse requests to the VOUT + φCD primary IC. Cable Drop As shown in the block diagram in Figure 4, the secondary control er Compensation is powered through a 4.45 V Regulator block by either VOUT or FORWARD pin connections to the SECONDARY BYPASS pin. The V
End of PCB
OUT SECONDARY BYPASS pin is connected to an external decoupling
Output Voltage
capacitor and fed internal y from the regulator block. The FORWARD pin also connects to the negative edge detection block used for both handshaking and timing to turn on the synchro- No-Load Onset of CC nous rectifier MOSFET (SR FET) connected to the SYNCHRONOUS
Load Current
Regulation RECTIFIER DRIVE pin. The FORWARD pin is also used to sense when PI-7863-010516 to turn off the SR FET in discontinuous mode operation when the voltage across the FET on resistance drops below V . SR(TH) Figure 8. Cable Drop Compensation Characteristics. In continuous mode operation the SR FET is turned off when the pulse request is sent to demand the next switching cycle, providing The lower feedback pin resistor must be tied to the SECONDARY excel ent synchronization free of any overlap for the FET turn-off GROUND pin (not ISENSE pin) to have output cable drop compensa- while operating in continuous mode. tion enabled.
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Rev. F 09/17 www.power.com Document Outline Product Highlights Highly Integrated, Compact Footprint EcoSmart - Energy Efficient Advanced Protection / Safety Features Full Safety and Regulatory Compliance Green Package Applications Description Output Power Table Pin Functional Description InnoSwitch-CP Functional Description InnoSwitch-CP Operation Applications Example Key application Considerations Selection of Components Recommendations for Circuit Board Layout Recommendations for EMI Reduction Recommendations for Audible Noise Suppression Recommendations for Transformer Design Quick Design Checklist Absolute Maximum Ratings Thermal Resistance Key Electrical Characteristics NOTES Typical Performance Characteristics eSOP-R16B Package Package Marking MSL Table ESD and Latch-Up Table Part Ordering Information