IWST-TR from iWatt, Inc.. Find the PDF Datasheet, Specifications and Distributor Information. IW Datasheet, IW PDF, Low Power Off Line Digital PWM Controller. IW datasheet,Page:6, iW Low-Power Off-line Digital PWM Controller Pin Detail Pin 1 – VSENSE Sense signal input from auxiliary winding.

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IW1688 Datasheet PDF

The rectifying diode D1 is reverse biased and the load current I O is supplied by the secondary capacitor C O. Home – IC Supply – Link. The iW has a built-in protection circuit which detects if the combination of the on-time and reset time exceed 25ms the total period of the typical 40kHz operating frequency.

Pin 4 datazheet V CC Power supply for the controller during normal operation. If the output voltage rises above the minimum threshold before soft-start is completed, the device assumes that the output load is very light and immediately changes to PFM operation.

P r There are two conditions for output short-circuit detection: If the system tries to go into CCM mode, the iW will send ns minimum on-time with datassheet ns delay. Power supply for the controller during normal operation. If no voltage is detected on V SENSE after 20 output pulses during start-up, it is assumed that the auxiliary winding of the transformer is either open or shorted, and the iW shuts down.


It also provides input undervoltage. This condition could occur when the output is shorted, or when there is a fault in the auxiliary winding.

iw datasheet & applicatoin notes – Datasheet Archive

The energy E g t is stored in the magnetizing inductance L M. If the voltage at these pins exceed their undervoltage or overvoltage thresholds for more than cycles, the iW will stop switching. Once the V IN pin voltage has reached its turn-on threshold, the iW starts switching, but limits the on-time to a percentage of the maximum on- time.

In order to regulate the output voltage within a tight.

It also provides input undervoltage and overvoltage protection. Pin 2 — GND Analog signal and power ground. The input line voltage is scaled using a resistor network. There are dataeheet conditions for output short-circuit detection:.

Due to some limitations of constant current mode. The current in Q 1 ramps up linearly at a rate of: The controller will continue to attempt to soft-start until.

The iW has been designed to work in constant-current. The iW includes functions that protect against input. The loop stability is guaranteed by design to provide at least 45 degrees of phase margin and —20dB of gain margin. CCM protection there ratasheet some trade-offs between size. Conduction Mode CCMwhich could saturate the. The iW has a built-in protection circuit which detects if.


The controller will shut off with 6 consecutive pulses after start-up. The iW uses the primary feedback only with no secondary feedback datxsheet. The controller will shut off with. This pin also provides the supply.

Home – IC Supply – Link. If the output voltage. The output voltage can be high enough to damage the output capacitor when the feedback loop is broken.

The input line voltage is datasneet. The controller will continue to attempt to soft-start until the error condition is removed. The output voltage can be high enough to damage the. V IN is used for line regulation. A short circuit condition is interpreted as any time the output. Pin 5 — V IN Sense signal input representing the average line voltage. When Q1 turns off, D1 conducts and the stored energy E g t is delivered to the output.

The iW will attempt to restart from any of these fault. The iW incorporates an internal soft-start function. However, the IC will remain biased which will discharge the. The soft-start time is set at 5 ms.