Cooperative primary and secondary current limiting to selectively limit aggregate and individual current outputs of a multi output converter

A converter circuit comprising:

• a transformer including a primary winding and a first and second secondary winding,
• input means for accepting a voltage source,
• switching means for coupling said input means to said primary winding,
• pulse means for generating a bias signal pulse and coupled to drive said switching means,
• current sensing means coupled for sensing a current conducted by said switching means,
• said pulse means coupled to and responsive to said current sensing means for limiting the duty cycle of said bias signal pulse in response to an overcurrent,
• wherein the improvement comprises:
• a normally disabled current conduction path coupled to be energized by a voltage generated by said first secondary winding,
• second current sensing means coupled for sensing an output current responsive to said first secondary winding, including
• means for enabling conduction in said conduction path in response to an overcurrent, and
• signaling means responsive to current flow in said conduction path, said signaling means coupled to said pulse means and having DC isolation characteristics to maintain DC isolation between said conduction path and said pulse means, whereby a signal output of said signaling means limits the duty cycle of said bias signal in response to an overcurrent responsive to said first secondary winding.

In a converter circuit including a power transformer, an input primary winding, a first secondary winding and at least a second secondary winding,

• first current limiting means to limit maximum current in said primary winding including current sensing means coupled to said primary winding and threshold responsive means coupled to actuate said current sensing means,
• an output circuit connected to said first secondary winding including a rectifying diode, a filter inductor and a flyback current path,
• a second current limiting means to limit maximum current in said output circuit including means to monitor current flow in said flyback current path,
• a signaling device and a gating device connected in series circuit, the series circuit shunting said first secondary winding, said gating device coupled to and being responsive to said means to monitor at a particular current threshold therein, and
• a receiving device coupled to said signaling device through a DC isolated coupling, said receiving device connected in parallel with said threshold responsive means and operative to actuate said first current limiting means.

In a converter circuit:

• a transformer including a primary winding and a secondary winding adapted to be coupled to a load to be energized,
• input means for accepting a voltage source,
• switching means for coupling said input means to said primary winding,
• pulse means for generating a bias signal pulse and coupled to drive said switching means, said pulse means responsive to a control signal to control a duty cycle of said bias signal pulse,
• a current conduction path coupled to be energized by an alternating voltage generated by at least a portion of said secondary winding,
• said current conduction path including unidirectional means to limit current flow therein to a singular direction in response to a particular voltage polarity represented by a predetermined voltage polarity of the alternating voltage generated by said secondary winding,
• current sensing means coupled for sensing an output current directly responsive to a periodic voltage of said secondary winding, including
• gating means coupled to said current sensing means and operative for enabling conduction in said current conduction path in response to an output current exceeding a predetermined threshold, and
• signaling means responsive to current flow in said current conduction path, said signaling means coupled to said pulse means and having DC isolation characteristics to maintain DC isolation between said current conduction path and said pulse means, whereby a signal output of said signaling means is operative as a control signal to limit a duty cycle of said bias signal pulse in response to an output current responsive to said secondary winding exceeding a predetermined threshold.

A converter circuit comprising:

• a transformer including a primary winding and a first and second secondary winding,
• input means for accepting a voltage source,
• switching means for coupling said input means to said primary winding,
• current threshold sensing means coupled to sense a particular current threshold conducted by said switching means,
• means for disabling conduction through said switching means responsive to said current threshold sensing means,
• wherein the improvement comprises:
• second current threshold sensing means coupled to sense a second current threshold of a current responsive to a voltage of said first secondary winding, said second current threshold sensing means including, a sensing impedance, a three electrode sense conductor device including a control electrode coupled to said sensing impedance and having a main conduction path, a signal transmission device having two input terminals connected to said main conduction path and to one terminal of said first secondary winding, respectively, said one terminal selected such that a voltage is generated during selected half cycle intervals when current is conducted by said sensing impedance to enable current flow through said main conduction path and said input terminals of said signal transmission device, said signal transmission device having DC isolated output terminals coupled to said means for disabling conduction.