Current detection circuit and pile-up detection circuit

A current detection circuit comprising:

• a low-pass filter, that a signal current is input, having a first terminal connected to a signal input terminal to which the signal current is input;
• a voltage-to-current converter circuit, that an output signal of the low-pass filter is input, having a first terminal connected to a second terminal of the low-pass filter and having a second terminal connected to the signal input terminal;
• and
• a comparator, that the output signal of the low-pass filter and an output signal of the voltage-to-current converter circuit are input, having a first input terminal and a second input terminal and outputting a signal according to a difference between a signal input through the first input terminal and a signal input through the second input terminal, the first input terminal being connected to the second terminal of the low-pass filter, and the second input terminal being connected to the second terminal of the voltage-to-current converter circuit,
• wherein a level shift circuit is connected between the second terminal of the voltage-to-current converter circuit and the signal input terminal.

A current detection circuit comprising:

• a low-pass filter, that a signal current is input, having a first terminal connected to a signal input terminal to which the signal current is input;
• a voltage-to-current converter circuit, that an output signal of the low-pass filter is input, having a first terminal connected to a second terminal of the low-pass filter and having a second terminal connected to the signal input terminal;
• and
• a comparator, that the input signal of the low-pass filter and an output signal of the voltage-to-current converter circuit are input, having a first input terminal and a second input terminal and outputting a signal according to a difference between a signal input through the first input terminal and a signal input through the second input terminal, the first input terminal being connected to the second terminal of the low-pass filter, and the second input terminal being connected to the second terminal of the voltage-to-current converter circuit,
• wherein the low-pass filter includes:
• a first capacitance element connected to the first terminal of the voltage-to-current converter circuit;
• a second capacitance element connected in series with the first capacitance element;
• and a first resistance element connected in parallel to the first capacitance element, and
• the first input terminal of the comparator is connected to a connection point between the first capacitance element and the second capacitance element.

A current detection circuit comprising:

• a low-pass filter;
• an impedance element having a first terminal connected to an input terminal of the low-pass filter and a second terminal connected to a signal input terminal to which a signal current is input;
• a voltage-to-current converter circuit having an input terminal connected to an output terminal of the low-pass filter and having an output terminal connected to the first terminal of the impedance element;
• and
• a comparator having a first input terminal and a second input terminal and outputting a signal according to a difference between a signal input through the first input terminal and a signal input through the second terminal, the first input terminal being input with a signal relating to an output signal of the low-pass filter, and the second input terminal being connected to the second terminal of the impedance element and the signal input terminal.

A pile-up detection circuit comprising:

• a first detection circuit to detect a signal current;
• a counter circuit to count a number of signal currents detected by the first detection circuit, and output a pile-up detection signal when a count value becomes 2;
• a second detection circuit to detect the signal current;
• and
• a control circuit to reset the count value of the counter circuit after a lapse of a predetermined period of time from the detection of the signal current by the second detection circuit.