Philips Semiconductors | Product data | |
|
|
|
Dual operational amplifier and 2.5 V shunt regulator | SA58605 | |
|
|
|
APPLICATION INFORMATION
The SA58605 may be used for various voltage control applications in which the input threshold voltage exceed 2.5 V for Amp ªAº and 154 mV for Amp ªBº. When either or both input threshold voltage is exceeded the output is pulled LOW. The output is connected to VCC with a
Figure 7 shows the schematic for a Universal Converter/Charger circuit in which the SA58605 Amp ªAº is used to monitor the B+ level of the converter/charger. Amp ªBº input is pulled to ground through a 390 Ω resistor and will remain there. The input to the Amp ªAº is maintained at 0.5 ⋅ B+ with the voltage divider of the two 1.5 kΩ resistors. As B+ drops below 5 V, the input to Amp ªAº of the
SA58605 follows and drops below 2.5 V. This causes the output (pin 1) to go HIGH and the LED is turned off. Q1 base drive is reduced and Q2 is increased. Thus, the PW modulation is increased, and B+ is able to satisfy the load requirements of the battery and circuitry. As B+ is increased above 5 V, it causes the input to Amp ªAº to increase above 2.5 V. Then, the output goes LOW and the LED is activated which turns on the detection diode. This increases the drive on Q1 and pulls down the base of Q2 reducing it base drive. With Q2 conducting less, the PW modulation is decreased and B+ is reduced. Under quasi-steady state, B+ is maintained at 5 V.
|
|
|
|
| 0.001 μF |
|
|
|
|
|
|
| B+ |
|
|
|
|
| /1 kV | T1 |
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
| ||
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
| 68 μH |
|
| |
|
|
|
|
| 56 kΩ |
|
|
|
|
|
| kΩ |
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
| 1.5 |
|
|
|
|
|
|
| D3 |
|
|
|
|
|
|
|
VIN = 85 ± 265 VAC |
|
|
| MUR160 |
|
| Ω |
|
|
| 1 kΩ |
| |
|
|
|
|
|
|
|
|
|
|
| |||
|
|
|
|
|
| 47kΩ | 1 M Ω | 100 | 5 |
| 4 |
|
|
|
|
|
|
|
|
|
|
|
| ||||
|
|
|
|
|
|
| SA58605 |
| 100 μF | ||||
|
|
|
| D1 |
| 800 μF |
|
|
|
|
| 0.1 μF | |
|
|
|
|
| /8 V |
|
| 1 | 2 | 3 | /16 V | ||
|
|
|
|
|
| Q3 |
|
| |||||
| L1 |
|
|
|
|
|
|
|
|
| kΩ |
| |
0.1 μF |
|
|
|
| 100 μF |
|
|
|
|
| |||
10 mH | 8.3 | μF |
| Q2 |
|
|
|
| 1.5 |
| |||
|
| 0.022 μF | /16 V |
|
|
|
|
|
| ||||
|
| /250 V |
|
|
|
|
|
|
|
| |||
|
|
|
|
|
|
|
|
|
|
| |||
|
|
|
| D2 |
|
| Q4 |
|
|
|
| Ω |
|
|
|
|
| 0.033 pF | Q1 |
| 390 Ω |
|
|
|
| 390 |
|
|
|
|
| 8.2 kΩ |
|
|
|
| 0.1 μF |
| |||
|
|
|
|
|
|
|
|
|
| ||||
|
|
|
|
|
| D4 |
|
|
|
| 0.22 Ω | GND | |
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
| SR01619 |
|
|
|
| 2.7 kΩ |
|
|
|
|
|
|
|
|
|
100 Ω 
|
|
| |
|
| ||
100 Ω | |||
| |||
Figure 7. Universal converter/charger application.
Components used in Figure 7
D1±D4: 1N5822
Q1±Q4: 2N3904
T1: | Cooper Electronic Technologies | |
| Part#: | |
| Primary: 47 YTurns of #29 AWG, Pin 4 = Start, Pin 5 = Finish | |
| Secondary: 5 Turns of 0.40 mm, Pins 1 and 2 = Start, Pins 7 and 8 = Finish | |
| Gap: Designed for total primary inductance of 1.24 mH | |
| Core: | |
Bobbin: Pins 3 and 6 removed, EE19
2003 Nov 12 | 6 |