Abstract: A PWM comprises a voltage transformation module, a voltage-sensing module and a timer. The voltage transformation module is configured to transform an input voltage into an output voltage. The voltage-sensing module is coupled to the voltage transformation module and configured to detect a voltage of a first terminal, wherein the voltage of the first terminal is proportional to the output voltage. The timer is configured to measure the time duration for which the voltage of the first terminal is lower than a reference voltage, wherein the timer initiates a short circuit signal when the time duration is greater than a predetermined value.

Abstract: A transmission mechanism for a toner cartridge for use in a printing apparatus includes a transmission tenon provided with a plurality of radial ribs each having a first chamfer, and a transmission sleeve internally provided with a plurality of radial grooves. Each of the grooves includes a second chamfer at the opening end of the transmission sleeve. The number of the grooves is twice the number of the ribs, which provides more positions allowing the transmission tenon to engage with the transmission sleeve. Thus, the ribs can engage with the grooves more quickly and accurately, whereas the coupling of the chamfers can reduce contact interference and allows smoother movement transmission. The occurrence of malfunctions can be thereby reduced.

Abstract: A PWM comprises a voltage transformation module, a voltage-sensing module and a timer. The voltage transformation module is configured to transform an input voltage into an output voltage. The voltage-sensing module is coupled to the voltage transformation module and configured to detect a voltage of a first terminal, wherein the voltage of the first terminal is proportional to the output voltage. The timer is configured to measure the time duration for which the voltage of the first terminal is lower than a reference voltage, wherein the timer initiates a short circuit signal when the time duration is greater than a predetermined value.

Abstract: A negative voltage detector includes a first n-channel transistor having a coupled gate node and drain node, a second n-channel transistor having a gate coupled to the gate of the first n-channel transistor, a first current source coupled to a drain of the first n-channel transistor, a second current source coupled to a drain of the second n-channel transistor, an output terminal coupled to the drain of the second n-channel transistor, and an input terminal coupled to a source of the first n-channel transistor. The gate voltage of the first n-channel transistor, i.e., the gate voltage of the second n-channel transistor, depends on its source voltage (the voltage of the input terminal), and the switching operation of the second n-channel transistor can be performed by controlling the voltage of the input terminal to change the output voltage of the output terminal.