Primary side control module and method for protection of MOSFET against burnout
First Claim
1. A primary side control module for a switching power supply of the type in which the flow of an input current through a primary winding of a transformer is controlled by a switch, said module comprising, in combination:
- a) a controller;
b) said controller being characterized by at least one port for receiving an input signal and at least one port for providing an output signal wherein said output signal controls said switch and said input signal comprises the throughput of said switch; and
c) a capacitor arranged within a circuit branch connecting said throughput of said switch to said port for receiving an input signal whereby said input signal comprises the derivative of said throughput of said switch.
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Accused Products
Abstract
A primary side control module for a switching power supply and a method for protecting a MOSFET that is controlled by a controller chip of the type that includes a timing network and switching drive output pins. The module includes the controller chip and the MOSFET. The controller chip provides a gating signal at the switching drive output pin to the MOSFET that may regulate the passage of current through the primary winding of a transformer of a switching power supply. A circuit branch provides communication between the throughput of the MOSFET and the timing network pin of the controller chip. A capacitor is provided within the circuit branch to differentiate the throughput and provide a signal characterized by downgoing spikes that result in protection of the MOSFET from burnout due to abnormalities associated with the internal operation of the controller chip.
33 Citations
14 Claims
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1. A primary side control module for a switching power supply of the type in which the flow of an input current through a primary winding of a transformer is controlled by a switch, said module comprising, in combination:
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a) a controller; b) said controller being characterized by at least one port for receiving an input signal and at least one port for providing an output signal wherein said output signal controls said switch and said input signal comprises the throughput of said switch; and c) a capacitor arranged within a circuit branch connecting said throughput of said switch to said port for receiving an input signal whereby said input signal comprises the derivative of said throughput of said switch. - View Dependent Claims (2, 3, 4, 5)
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6. A method for protecting a switch against excessive current throughput in response to a gating signal provided at a switching drive output pin of a controller of the fixed frequency current mode pulse width type comprising the steps of:
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a) turning said switch “
ON”
in response to a leading edge of said gating signal; andb) receiving said current throughput from said switch;
thenc) differentiating said current throughput; and d) applying said differentiated current throughput to a timing network pin of said controller to thereby generate a trailing edge of said gating signal; and e) applying said trailing edge of said gating signal to said switch to turn “
OFF”
said switch; and
thenf) repeating steps a through e until there exists no further current throughput. - View Dependent Claims (7, 8, 9)
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10. A method for controlling a pulse width modulated signal provided at a switching drive output pin of a controller of the fixed frequency current mode pulse width modulation type comprising the steps of:
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a) arranging an RC network for providing a first signal at a timing network pin of said controller; and b) providing a second signal at said timing network pin of said controller wherein said second signal is characterized by a plurality of downwardly-directed spikes, each of said downwardly-directed spikes being synchronized with a trailing edge of a pulse width modulated waveform output at said switching drive output pin of said controller. - View Dependent Claims (11, 12, 13, 14)
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Specification