Electronic Components Datasheet Search |
|
PT4224N Datasheet(PDF) 4 Page - Texas Instruments |
|
PT4224N Datasheet(HTML) 4 Page - Texas Instruments |
4 / 8 page For technical support and more information, see inside back cover or visit www.ti.com Application Notes PT4220/4240 Series Using the Remote On/Off with the PT4220/4240 Isolated 10W Excalibur DC/DC Converters For applications requiring output voltage On/Off control, the PT4220/4240 DC/DC converter series incorporates a “Remote On/Off” control (pin 1). This feature can be used to switch the module off without removing the applied input source voltage. The converter functions normally with Pin 1 open-circuit, providing a regulated output voltage when a valid source voltage is applied to +Vin (pin 5), with respect to –Vin (pin 3). When a low-level 1 ground signal is applied to pin 1, the converter output will be turned off. Figure 1 shows an application schematic, which details the typical use of the Remote On/Off function. Note the discrete transistor (Q1). The pin has its own internal pull-up, allowing it to be controlled with an open-collector or open-drain device (See notes 2 & 3). Table 1 gives the threshold requirements. When placed in the “Off” state, the standby current drawn from the input source is typically reduced to less than 1mA. Table 1; Pin 1 Remote On/Off Control Parameters 1 Parameter Min Typ Max Enable (VIH) 4.5V — — Disable (VIL) — — 0.8V Vo/c [Open-Circuit] 5.0V Iin [pin 1 at –Vin] — — –0.5mA Notes: 1. The Remote On/Off control uses –Vin (pin 3) as its ground reference. All voltages specified are with respect to –Vin. 2. Use an open-collector device (preferably a discrete transistor) for the Remote On/Off input. A pull-up resistor is not necessary. To disable the output voltage, the control pin should be pulled low to less than +0.8VDC. 3. The Remote On/Off pin may be controlled with devices that have a totem-pole output. This is provided the drive voltage meets the threshold requirements in Table 1. Do not apply more than +20V. If a TTL gate is used, a pull-up resistor may be required to the logic supply voltage. 4. The PT4220/4240 converters incorporate an “Under- Voltage Lockout” (UVLO). The UVLO will keep the module off when the input voltage to the converter is low, regardless of the state of the Remote On/Off control. Table 2 gives the UVLO input voltage thresholds. Figure 1 Turn-On Time: In the circuit of Figure 1, turning Q1 on applies a low-voltage to pin 1 and disables the converter output. Correspondingly, turning Q1 off allows pin 1 to be pulled high by an internal pull-up resistor. The con- verter produces a regulated output voltage within 60ms. Figure 2 shows shows the output response of a PT4223 (5.0V) following the turn-off of Q1. The turn off of Q1 corresponds to the drop in Q1 Vgs. Although the rise- time of the output voltage is short (<5ms), the indicated delay time will vary depending upon the input voltage and the module’s internal timing. The waveform was measured with a 48Vdc input voltage, and a 1.4A resis- tive load. Figure 2 R1 10k Q1 BSS138 +V o -V o +V in -V in Vdd 1 =OFF Note 1 U1a Note 1 Note 1 PT4220/4240 + V out -Vout +Vin -Vin Remote On/Off V o (adj) 1 3 5 8, 9 6, 7 10 Table 2; UVLO Thresholds 4 Series Vin Range UVLO Threshold PT4220 36 – 75V 32V ±2V PT4240 18 – 36V 15.8V ±2V Vo (2V/Div) Iin (0.2A/Div) Q1Vgs (10V/Div) HORIZ SCALE: 10ms/Div Delay Time |
Similar Part No. - PT4224N |
|
Similar Description - PT4224N |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |