Infineon Technologies Austria Ag

Infineon Technologies Ag

Mladen Ivankovic

Fred Sawyer

Xiaowu Gong

In some embodiments, a power system includes an integrated circuit (IC). The IC includes a first switching transistor having a load path coupled between a sensing terminal of the IC and a first terminal of the IC. The first terminal of the IC is configured to be coupled to a first load path terminal of a second switching transistor. The IC also includes a first diode coupled between the first terminal of the IC and a second terminal of the IC. The second terminal is configured to be coupled to an auxiliary winding of the power system. The IC further includes a first driver circuit having an output coupled to a third terminal of the IC. The third terminal is configured to be coupled to a control node of the second switching transistor.

System and method for a cascode switch

An embodiment method for designing a power converter system includes receiving, by a processor, power converter design parameters. The design parameters include a minimum DC input voltage Vand a maximum DC input voltage V, a minimum switching frequency fand a maximum switching frequency fof a switching bridge of the power converter, and a target output voltage and a target output power. The method also includes calculating, by the processor, a first power converter configuration. The first power converter configuration includes a calculated magnetizing inductance Lequal to Rtan(&#x3c6;)(2&#x3c0;f), where &#x3c6; is a load angle complement equal to a sin(VV), and Ris an equivalent reflected load resistance of the power converter. The first power converter configuration also includes a calculated resonant inductance Lequal to Lcos(&#x3c6;)(ff&#x2212;1)and a calculated resonant capacitance Cequal to L(2&#x3c0;f).

System and method for LLC converter design

In accordance with an embodiment, a circuit includes a first and a second switching transistors configured to be coupled in series between a first reference voltage terminal and a transformer. The circuit also includes a first diode coupled between a first drain of the first switching transistor and a first input terminal. The first diode is configured to clamp a voltage of the first drain to a voltage of the first input terminal. The circuit further includes a switching circuit coupled between the second switching transistor and the first input terminal. The switching circuit is configured to connect a second source of the second switching transistor to a second gate of the second switching transistor when a voltage of the second source exceeds the voltage of the first input terminal.

Driver for the high side switch of the cascode switch

A two-transistor flyback converter includes a transformer having a primary side and a secondary side, a first transistor connected between an input voltage source and a first terminal of the primary side, a second transistor connected between ground and a second terminal of the primary side, and a diode directly connected between the first terminal of the primary side and ground. The first and second transistors are operable to switch on and off simultaneously and with no current return from the primary side to the input voltage source when the input voltage source is less than a reflected voltage from the secondary side.

Buck-flyback converter

A circuit includes a transformer having a first winding and a second winding, an input connected to a first terminal of the first winding, a first power transistor and a second power transistor. The first power transistor has a source, a gate, and a drain connected to a second terminal of the first winding. The second power transistor has a source connected to ground, a gate connected to a pulsed voltage drive source and a drain connected to the source of the first power transistor. The gate of the first power transistor is connected to a DC source or the same pulsed voltage drive source as the gate of the second power transistor. The first power transistor actively turns off independent of load current. Other circuit embodiments and corresponding load switching methods are also provided.

Half bridge flyback and forward

An LED driver includes a transformer, current control loop and current adjustment circuit. The primary side of the transformer transfers energy to the secondary side of the transformer responsive to an input signal. The secondary side delivers output current to one or more LEDs at a magnitude corresponding to the amount of energy transferred to the secondary side. The current control loop controls current in the primary side so that the output current equals a reference current signal. The current adjustment circuit injects a current adjustment signal into the current control loop responsive to a phase-cut signal which removes a portion of the input signal. The current control loop also decreases the current in the primary side responsive to the current adjustment signal so that a brightness of each LED connected to the secondary side is decreased by an amount corresponding to the magnitude of the current adjustment signal.

Method and circuit for LED driver dimming

A cascode switch includes a first power transistor configured to be coupled to a load and a second power transistor coupled in series with the first power transistor so that the second power transistor is between ground and the first power transistor. The second power transistor is operable to switch on and off responsive to a pulse source coupled to a gate of the second power transistor. The first power transistor is operable to switch on and off responsive to the same pulse source as the second power transistor or a DC source coupled to a gate of the first power transistor. Alternatively or in addition, a transistor device is coupled to the gate of the first power transistor and operable to actively turn off the first power transistor independent of the load current.

Cascode switch with robust turn on and turn off

A circuit includes a high-side switch, a low-side switch, a diode, a transformer having a primary winding and a secondary windowing, and an input connected to a first terminal of the primary winding. The high-side switch has a source, a gate connected to a drive source and a drain connected to a second terminal of the primary winding. The low-side switch has a source connected to ground, a gate connected to a drive source and a drain connected to the source of the high-side switch. The diode is connected between the gate of the high-side switch and the first terminal of the primary winding. The diode forms a current loop with the primary winding and the high-side switch to circulate current when low side switch is off until the high side switch turns off.

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Oakville, Canada

Mladen Ivankovic