Datasheet InnoSwitch3-EP (Power Integrations) - 5

InnoSwitch3-EP
The auto-restart is reset as soon as an AC reset occurs.
SOA Protection
P: Primary Chip In the event that there are two consecutive cycles where the I is LIM S: Secondary Chip Start reached within ~500 ns (the blanking time + current limit delay time), P: Powered Up, Switching the control er will skip 2.5 cycles or ~25 ms (based on full frequency S: Powering Up of 100 kHz). This provides sufficient time for the transformer to reset with large capacitive loads without extending the start-up time.
Secondary Rectifier/SR Switch Short Protection (SRS)
P: Auto-Restart In the event that the output diode or SR FET is short-circuited before S: Powering Up or during the primary conduction cycle, the drain current (prior to the end of the leading edge blanking time) can be much higher than the tAR(OFF) maximum current limit threshold. If the control er turns the high- voltage power switch off, the resulting peak drain voltage could S: Has powered No P: Goes to Auto-Restart Off exceed the rated BV of the device, resulting in catastrophic failure DSS up within tAR S: Bypass Discharging even with minimum on-time. To address this issue, the control er features a circuit that reacts Yes t when the drain current exceeds the maximum current limit threshold AR prior to the end of leading-edge blanking time. If the leading-edge P: Switching S: Sends Handshaking Pulses current exceeds current limit within a cycle (200 ns), the primary control er will trigger a 30 ms off-time event. SOA mode is triggered if there are two consecutive cycles above current limit within t LES (~500 ns). SRS mode also triggers t off-time, if the current AR(OFF)SH limit is reached within 200 ns after a 30 ms off-time. P: Has Received No P: Continuous Switching Handshaking S: Doesn’t Take Control SRS protection is not available on INN3679C-INN3670C. Pulses
Input Line Voltage Monitoring
Yes The UNDER/OVER INPUT VOLTAGE pin is used for input undervoltage and overvoltage sensing and protection. P: Stops Switching, Hands Over Control to Secondary A 4 MΩ resistor is tied between the high-voltage DC bulk capacitor after the bridge (or to the AC side of the bridge rectifier for fast AC reset) and the UNDER/OVER INPUT VOLTAGE pin to enable this functionality. This function can be disabled by shorting the UNDER/ OVER INPUT VOLTAGE pin to SOURCE pin. S: Has Taken No P: Not Switching Control? S: Doesn’t Take Control At power-up, after the primary bypass capacitor is charged and the ILIM state is latched, and prior to switching, the state of the UNDER/ Yes OVER INPUT VOLTAGE pin is checked to confirm that it is above the brown-in and below the overvoltage shutdown thresholds. End of Handshaking, Secondary Control Mode In normal operation, if the UNDER/OVER INPUT VOLTAGE pin current fal s below the brown-out threshold and remains below brown-in for PI-7416a-102116 longer than t , the control er enters auto-restart. Switching will only UV- resume once the UNDER/OVER INPUT VOLTAGE pin current is above the brown-in threshold. Figure 7. Primary-Secondary Handshake Flowchart. In the event that the UNDER/OVER INPUT VOLTAGE pin current is above the overvoltage threshold, the control er will also enter beginning of the next switching cycle. auto-restart. Again, switching will only resume once the UNDER/
Primary-Secondary Handshake
OVER INPUT VOLTAGE pin current has returned to within its normal At start-up, the primary-side initial y switches without any feedback operating range. information (this is very similar to the operation of a standard TOPSwitch™, TinySwitch™ or LinkSwitch™ control ers). The input line UV/OV function makes use of an internal high-voltage Switch on the UNDER/OVER INPUT VOLTAGE pin to reduce power If no feedback signals are received during the auto-restart on-time consumption. If the cycle off-time t is greater than 50 ms, the (t ), the primary goes into auto-restart mode. Under normal OFF AR internal high-voltage Switch will disconnect the external 4 MΩ resistor conditions, the secondary control er will power-up via the FORWARD from the internal IC to eliminate current drawn through the pin or from the OUTPUT VOLTAGE pin and take over control. From 4 MΩ resistor. The line sensing function will activate again at the this point onwards the secondary controls switching. If the primary control er stops switching or does not respond to cycle requests from the secondary during normal operation (when the secondary has control), the handshake protocol is initiated to ensure that the secondary is ready to assume control once the primary begins to switch again. An additional handshake is also triggered if the secondary detects that the primary is providing more cycles than
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Rev. G 07/19 www.power.com Document Outline Product Highlights Description Output Power Table Pin Functional Description InnoSwitch3-EP Functional Description Primary Controller Secondary Controller Applications Example Key Application Considerations Selection of Components Components for InnoSwitch3-EP Primary-Side Circuit Components for InnoSwitch3-EP Secondary-Side Circuit Recommendations for Circuit Board Layout Layout Example Quick Design Checklist Absolute Maximum Ratings Thermal Resistance Typical Performance Curves InSOP-24D Package Drawing InSOP-24D Package Marking Part Ordering Table MSL Table ESD and Latch-Up Table Part Ordering Information