Balanced delta current method for current control in a hysteretic power supply

A method for controlling current in a switching voltage controller with a sequential switching circuit for energizing a storage element by a supply voltage source, comprising the steps of:

• sensing current flowing through the storage element to provide a current sense signal indicative of the current;
• providing a control signal indicative of the voltage difference between a reference voltage source and the output of the switching voltage controller;
• providing a valley signal with a voltage a first voltage differential .DELTA.' below the voltage of the control signal and a peak signal with a voltage a second voltage differential .DELTA." above the voltage of the control signal, wherein .DELTA.' and .DELTA." are responsive to the supply voltage source such that changes in .DELTA.' and .DELTA." for a given change in the voltage of the supply voltage source are substantially equal to each other;
• switching the sequential switching circuit to be in a first state when there is a first relationship between the current sense signal voltage and the valley signal voltage;
• and
• switching the sequential switching circuit to be in a second state when there is a second relationship between the current sense signal voltage and the peak signal voltage.

A switching voltage controller with an output voltage terminal, a supply voltage terminal, and a gating signal terminal, the switching voltage controller comprising:

• a balanced delta current circuit, including,
• a first input for a control signal, where the control signal is responsive to the voltage at the output voltage terminal;
• a second input coupled to the supply voltage terminal;
• a first output to provide a peak signal and a second output to provide a valley signal, wherein the valley signal is at a voltage a first voltage differential .DELTA.' below the voltage at the first input and the peak signal is at a voltage a second voltage differential .DELTA." above the voltage at the first input such that .DELTA.' and .DELTA." are functionally dependent upon the voltage at the second input and changes in .DELTA.' and .DELTA." for a given change in the voltage at the second input are substantially equal to each other;
• and
• a sequential circuit, including,
• a first input coupled to the first output of the balanced delta current circuit;
• a second input coupled to the second output of the balanced delta current circuit;
• a third input responsive to a current sense signal;
• and
• an output coupled to the gating signal terminal for providing a gating signal, wherein the gating signal is responsive to the state of the sequential circuit, wherein the sequential circuit is in a first state when there is a first relationship between the current sense signal and the peak signal and is in a second state when there is a second relationship between the current sense signal and the valley signal.

A switching voltage controller with a supply voltage input, a reference voltage input, and an output, for regulating the voltage at the output by controlling a current flowing through a switch when an electromagnetic energy storage element is coupled to the switch and the output, the switching voltage controller comprising:

• a switch coupled to the supply voltage input, wherein when a supply voltage source is coupled to the supply voltage input and an electromagnetic energy storage element is coupled to the switch and the output, energy is increasing in the storage element when the switch is ON and is decreasing when the switch is OFF;
• a current sense amplifier coupled to the output, wherein the current sense signal output voltage is indicative of a current flowing through an electromagnetic energy storage element when coupled to the switch and the output;
• an error amplifier coupled to the voltage controller output and the reference voltage input, wherein the error amplifier output voltage is indicative of the voltage difference between the voltage controller output and a reference voltage source coupled to the reference voltage input;
• a voltage-controlled current sink coupled to the supply voltage input, wherein the current sink is responsive to a supply voltage source coupled to the supply voltage input;
• a first resistor with a first terminal coupled to the voltage-controlled current sink and a second terminal coupled to the output of the error amplifier;
• a first voltage-controlled current source coupled to the supply voltage input, wherein the first current source is responsive to a supply voltage source coupled to the supply voltage input;
• a second resistor with a first terminal coupled to the first current source and a second terminal coupled to the output of the error amplifier;
• and
• a sequential circuit coupled to the output of the current sense amplifier, the first terminal of the first resistor, the first terminal of the second resistor, and the switch, wherein the sequential circuit has a first state and a second state;
• wherein the sequential circuit is in the first state when there is a first relationship between the current sense amplifier output voltage and the voltage at the first terminal of the first resistor and is in the second state when there is a second relationship between the current sense amplifier output voltage and the voltage at the first terminal of the second resistor, wherein the switch changes state when the sequential circuit changes state.