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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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. The energy E g t is stored in the magnetizing inductance L M. The input line voltage is scaled. Home – IC Supply – Link. The controller will continue to attempt to soft-start until.
In order to regulate the output voltage within a tight. Power supply for the controller during normal operation. The output voltage can be high enough to damage the output capacitor when the feedback loop is broken.
The input line voltage is scaled using a resistor network. Sense signal input from auxiliary winding. Home – IC Iw1868 – Link.
A short circuit condition is interpreted as any time the output. The output voltage can be high enough to damage the. If the output voltage. The controller will datasueet off with.
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This pin also provides the supply current to the IC during start-up. Thereafter, the on-time will be modulated by the line voltage and the off-time is modulated by the load current. The nominal switching frequency is 40 kHz. Pin 5 — V IN Sense signal input representing the average line voltage.
If the voltage at these pins exceed their undervoltage or overvoltage thresholds for more than cycles, the iW will stop switching. The iW will attempt to restart from any of these fault. It also provides input undervoltage. This pin also provides the supply. This condition could occur when the output is shorted, or when there is a fault in the auxiliary winding.
The iW has been designed to work in constant-current. Conduction Mode CCMwhich could saturate the. CCM protection there are some trade-offs between size.
The iW uses the primary feedback only with no secondary feedback datasheft. The controller will shut off with 6 consecutive pulses after start-up.
Pin 4 — V CC Power supply for the controller during normal operation. Pin 2 — GND Analog signal and power ground. 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. P r There are two conditions for output short-circuit detection: V IN is used for line regulation. Due to some limitations of constant current mode.
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 a ns delay.
As the output load. The controller will continue to attempt datashet soft-start until the error condition is removed. However, the IC will remain biased which will discharge the. The voltage across L M is v g tassuming the voltage dropped across Q 1 is zero.
Thereafter, the on-time will be modulated by the line voltage. The soft-start time is set at 5 ms. Sense signal input datashet the average line voltage. If the output voltage rises above the minimum threshold.
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If the output voltage rises above the minimum threshold before soft-start is completed, the device assumes that the output load is very light datasheft immediately changes to PFM operation. The iW includes functions that protect against input.
The current in Q 1 ramps up linearly at a rate of: When Q1 turns off, D1 conducts and the stored energy E g t is delivered to the output. The iW incorporates datashret internal soft-start function. It also provides input undervoltage and overvoltage protection.
The dagasheet diode D1 is reverse biased and the load current I O is supplied by the secondary capacitor C O. This provides the secondary voltage feedback used for output regulation.
The loop stability is guaranteed by design to provide at least 45 degrees of phase margin and —20dB of gain margin.