IW1688 DATASHEET PDF

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

This condition could occur when the output is shorted, or when there is a fault in the auxiliary winding. Pin 5 — V IN Sense signal input representing the ow1688 line voltage. Thereafter, the on-time will be modulated by the line voltage and the off-time is modulated by the load current. The voltage across L M is v g tassuming the voltage dropped across Q 1 is zero. This provides the secondary voltage feedback used for output regulation. If the output voltage.

IW Datasheet PDF –

The controller will continue to attempt to soft-start until the error condition is removed. 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 iw1868 typical 40kHz operating frequency. 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.

When Q1 turns off, D1 conducts and the stored energy E g t is delivered to the output.

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The controller will shut off with 6 consecutive pulses after start-up. The iW will attempt to restart from any of these fault.

Thereafter, the on-time will be modulated by the line voltage.

V IN is used for line regulation. Home – IC Supply – Link.

IW1688 Datasheet PDF

The iW uses the primary feedback only with no secondary feedback loop. This pin also provides the supply current to the IC during start-up.

The rectifying diode D1 is reverse biased and the load current I O is supplied by the secondary capacitor C O. The output voltage can be high enough to damage the output capacitor when the feedback loop is broken. The input line voltage is scaled. Due to some limitations of constant current mode. If the voltage at these pins exceed their undervoltage or overvoltage thresholds for more than cycles, the iW will stop switching.

Pin 4 — V CC Power supply for the controller during normal operation. 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.

The iW has a built-in protection circuit which detects if. It also provides input undervoltage and overvoltage protection. The controller will continue to attempt to soft-start datashret. This pin also provides the supply.

Pin 2 — GND Analog signal and power ground. The energy E g t is stored in the magnetizing inductance L M. A short circuit condition is interpreted as any time the output. The controller will shut off with.

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The iW has been designed to work in constant-current. The nominal switching frequency is 40 kHz. If the system dafasheet to go into CCM mode, the iW will send ns minimum on-time with a ns delay.

IW Datasheet PDF – iWatt

The iW includes functions that protect against input. Home – IC Supply – Link. The current in Q 1 ramps up linearly at a rate of: 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.

However, the IC will remain biased which will discharge the. The soft-start time is set at 5 ms. As the i1688 load. It also provides input undervoltage. Sense signal input representing the average line voltage. Conduction Mode CCMwhich could saturate the. The input line voltage is scaled using a resistor network.

Sense signal input from auxiliary winding.

The output voltage can be high enough to damage the. CCM protection there are some trade-offs between size.

Power supply for the controller during normal operation.