Datasheet InnoSwitch3-MX (Power Integrations) - 6

InnoSwitch3-MX
As an additional safety measure the primary will pause for an auto-restart on-time period, t (~82 ms), before switching. During AR this “wait” time, the primary will “listen” for secondary requests. If it P: Primary Chip sees two consecutive secondary requests, separated by ~30 µs, the S: Secondary Chip Start primary will infer secondary control and begin switching in slave P: Powered Up, Switching mode. If no pulses occur during the t “wait” period, the primary S: Powering Up AR will begin switching under primary control until handshake pulses are received.
Audible Noise Reduction Engine
P: Auto-Restart The InnoSwitch3-MX features an active audible noise reduction mode S: Powering Up whereby the control er (via a “frequency skipping” mode of operation) avoids the resonant band (where the mechanical structure of the 2s power supply is most likely to resonate − increasing noise amplitude) between 7 kHz and 12 kHz – 142 µs and 83 µs. If a secondary control er switch request occurs within this time window from the last S: Has powered No P: Goes to Auto-Restart Off up within t conduction cycle, the gate drive to the power switch is inhibited. AR S: Bypass Discharging
Secondary Controller
The IC is powered by the SECONDARY BYPASS (BPS) pin. This pin is Yes t normal y connected to the InnoMux which, will provide power to the AR secondary controller. P: Switching S: Sends Handshaking Pulses The interface to InnoMux consists of four pins; the REQ pin receives requests for a new primary switching cycle. These requests are sent to the primary using the flux link. The ACK pin acknowledges the request when the pulse is sent over the flux link. The FWC and the P: Has Received No SR pins provide further handshaking and timing signals for the P: Continuous Switching Handshaking S: Doesn’t Take Control InnoMux. Pulses The FORWARD pin connects to the negative edge detection block Yes used for both handshaking and timing to turn on the SR FET connected to the SYNCHRONOUS RECTIFIER DRIVE pin. The P: Stops Switching, Hands FORWARD pin is used to sense when to turn off the SR FET in Over Control to Secondary discontinuous mode operation when the voltage across the FET on resistance drops below the V threshold. SR(TH) In continuous conduction mode (CCM); operation of the SR FET is turned off when the pulse to demand the next switching cycle is sent S: Has Taken No P: Not Switching to the primary control er, providing excel ent synchronous operation, Control? S: Doesn’t Take Control free of any overlap for the FET turn-off while operating in continuous mode. Yes
Minimum Off-Time
The secondary control er initiates a cycle request using the inductive End of Handshaking, connection to the primary. The maximum frequency of secondary Secondary Control Mode cycle requests is limited by a minimum cycle off-time of t . This OFF(MIN) is in order to ensure that there is sufficient reset time after primary PI-7416-102116 conduction to deliver energy to the load. Figure 7. Primary-Secondary Handshake Flow Chart.
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Rev. B 03/19 www.power.com Document Outline Product Highlights Description Output Power Table Pin Functional Description InnoSwitch3-MX Functional Description Absolute Maximum Ratings Thermal Resistance Key Electrical Characteristics InSOP-24D Package Drawing Part Ordering Information