The TL284x and TL384x 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. Some of the internally implemented circuits are an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference 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. Major differences between members of these series are the UVLO thresholds and maximum duty-cycle ranges.
The TL284x and TL384x series of control integrated circuits provide the features necessary to implement off-line or dc-to-dc fixed-frequency current-mode control schemes with a minimum number of external components. These devices are optimized for off-line and dc-to-dc converters and include features such as automatic feed-forward compensation, enhanced load-response characteristics, and double-pulse suppression.
| Oscillator frequency | 100 to 500 kHz |
|---|---|
| Supply voltage | 30 V |
| Operating temperature (TL284x) | -40°C to 85°C |
| Operating temperature (TL384x) | 0°C to 70°C |
| Maximum duty cycle (TLx842, TLx843) | 95% to 100% |
| Output noise voltage | 50 µV |
The start-up current is less than 1 mA.
The typical oscillator frequency is 500 kHz.
The typical output voltage is 5 V.