A Long Reset-Time Power-On Reset Circuit With Brown-Out Detection Capability

Compact Power-on Reset Circuit Using a Switched Capacitor

“…The POR signal holds target circuits in the reset state until the power supply voltage reaches a steady-state level at which the target circuits can operate correctly [1]. During the power-up transitional period, memory elements in the circuits, such as flip-flops and latches, should be properly initialized.…”

“…In [1,2], a simple resistor-capacitor (RC) delay-type POR circuit was analyzed. This simple conventional POR circuit was built upon an RC delay element and a Schmitt trigger inverter.…”

“…There are two approaches to solving the problem of the conventional POR circuit. The first approach is to increase the pulse width of the POR signal using delay elements [1][2][3]. In Section II, the previous works in [1] and [3] are described in detail.…”

“…The first approach is to increase the pulse width of the POR signal using delay elements [1][2][3]. In Section II, the previous works in [1] and [3] are described in detail. The second approach is to generate a POR signal until the supply voltage reaches a reference voltage that has been implemented in many cases using bandgap reference circuits [4][5][6].…”

“…1 shows the timing diagram of supply voltage V DD and the reset signal. V DDF is the steady-state value of the supply voltage, V osc is the lowest supply level at which the clock generator starts to work, and V min is the minimum voltage of the supply, at which the reset switch is turned on by the reset signal (i.e., the threshold of the reset switch) [1]. T 0 is the rising time of the supply voltage, and T POR is the reset time counted from the moment when the reset switch turns on.…”