Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
265 words
In blocking oscillator power pack of the type in which a switching transistor is connected in series with the primary winding of a transformer connected to a rectified line voltage current to be switched, in which a first secondary winding is provided for connection to a load, in which a second secondary winding derives a control voltage representing the voltage across the primary winding, and in which a control circuit is connected between the second secondary winding and a control electrode of the switching transistor, said control circuit also connected to the rectified line voltage supply providing an actual value and including a reference value generator and operable to control the switching of the switching transistor, the improvement comprising: an anti-disruption circuit in the control circuit connected to the secondary winding and operable to inhibit conduction of the switching transistor in response to the control voltage exceeding a predetermined limit value, said control circuit further comprising a pulse width regulator connected to the control electrode of the switching transistor, gate means connected between said pulse width regulator and said anti-disruption circuit, and means in said anti-disruption circuit for defining the predetermined limit value and comparing the control voltage thereto, and said anti-disruption circuit further comprising a capacitor connected to a reference potential, a Zener diode connected to said capacitor, an operational amplifier including an output connected to said gate means, a first input connected to said Zener diode, and a second input connected to a reference potential, and a diode connecting the junction of said Zener diode and said capacitor to the second secondary winding.
Claim 2
Dependent Claim
265 words
In blocking oscillator power pack of the type in which a switching transistor is connected in series with the primary winding of a transformer connected to a rectified line voltage current to be switched, in which a first secondary winding is provided for connection to a load, in which a second secondary winding derives a control voltage representing the voltage across the primary winding, and in which a control circuit is connected between the second secondary winding and a control electrode of the switching transistor, said control circuit also connected to the rectified line voltage supply providing an actual value and including a reference value generator and operable to control the switching of the switching transistor, the improvement comprising: an anti-disruption circuit in the control circuit connected to the secondary winding and operable to inhibit conduction of the switching transistor in response to the control voltage exceeding a predetermined limit value, said control circuit further comprising a pulse width regulator connected to the control electrode of the switching transistor, gate means connected between said pulse width regulator and said anti-disruption circuit, and means in said anti-disruption circuit for defining the predetermined limit value and comparing the control voltage thereto, and said anti-disruption circuit further comprising a capacitor connected to a reference potential, a Zener diode connected to said capacitor, an operational amplifier including an output connected to said gate means, a first input connected to said Zener diode, and a second input connected to a reference potential, and a diode connecting the junction of said Zener diode and said capacitor to the second secondary winding.
Claim 3
Dependent Claim
25 words
The improved power pack of claim 1, and further comprising: a resistor connected to said first input and to said output of said operational amplifier.