沟道MOSFET ,为低时,它处于关闭状态。
The TL284xB and TL384xB series of control integrated circuits provide the features that are necessary to
implement off-line or dc-to-dc fixed-frequency current-mode control schemes, with a minimum number of
external components. Internally implemented circuits include an undervoltage lockout (UVLO) and a precision
reference that is trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure
latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a
totem-pole output stage designed to source or sink high-peak current. The output stage, suitable for driving
N-channel MOSFETs, is low when it is in the off state.
The TL284xB and TL384xB series are pin compatible with the standard TL284x and TL384x with the following
improvements. The start-up current is specified to be 0.5 mA (max), while the oscillator discharge current is
trimmed to 8.3 mA (typ). In addition, during undervoltage lockout conditions, the output has a maximum
saturation voltage of 1.2 V while sinking 10 mA (VCC = 5 V).