SG3524D

完整的脉宽调制 (PWM) 电源控制电路用于单端或推挽应用的非限定输出8mA（典型值）待机电流 SGx524 is a fixed-frequency pulse-width-modulation (PWM) voltage-regulator control circuit. The regulator operates at a fixed frequency that is programmed by one timing resistor, RT, and one timing capacitor, CT. RT establishes a constant charging current for CT. This results in a linear voltage ramp at CT, which is fed to the comparator, providing linear control of the output pulse duration (width) by the error amplifier. The SGx524 contains an onboard 5-V regulator that serves as a reference, as well as supplying the SGx524 internal regulator control circuitry. The internal reference voltage is divided externally by a resistor ladder network to provide a reference within the common-mode range of the error amplifier, or an external reference can be used. The output is sensed by a second resistor divider network and the error signal is amplified. This voltage is then compared to the linear voltage ramp at CT. The resulting modulated pulse out of the high-gain comparator then is steered to the appropriate output pass transistor (Q1 or Q2) by the pulse-steering flip-flop, which is synchronously toggled by the oscillator output. The oscillator output pulse also serves as a blanking pulse to ensure both outputs are never on simultaneously during the transition times. The duration of the blanking pulse is controlled by the value of CT. The outputs may be applied in a push-pull configuration in which their frequency is one-half that of the base oscillator, or paralleled for single-ended applications in which the frequency is equal to that of the oscillator. The output of the error amplifier shares a common input to the comparator with the current-limiting and shut-down circuitry and can be overridden by signals from either of these inputs. This common point is pinned out externally via the COMP pin, which can be employed to either control the gain of the error amplifier or to compen

• 变压器耦合直流/直流转换器
• 任意极性的开关稳压器
• 稳压电源
• 逆变器
• 无变压器电压加倍器
• 极性变换器