Bose Lifestyle 48 Руководство по устранению неполадок - Страница 6

Просмотреть онлайн или скачать pdf Руководство по устранению неполадок для Динамики Bose Lifestyle 48. Bose Lifestyle 48 32 страницы. Personal music center ii - owner's guide
Также для Bose Lifestyle 48: Руководство по установке (42 страниц), Руководство (29 страниц), Руководство по установке (36 страниц), Руководство пользователя (25 страниц), Руководство пользователя (24 страниц), Руководство пользователя (13 страниц), Руководство по быстрой настройке (3 страниц), Руководство пользователя (30 страниц)

Bose Lifestyle 48 Руководство по устранению неполадок
PS18/28/35 Troubleshooting Guide
Theory of Operation
The IC has two enable pins, one of which (pin-8) disables the operation while the other (pin-9)
enables the operation. A voltage pulse higher than 0.6V at pin-8 shuts down the IC and a voltage
pulse higher than 1.2V at pin-9 wakes up the IC. An opamp, an under voltage lockout circuit, and a
soft start circuit are also built into the IC.
Figure 3 is a circuit diagram that shows how the IC is used in the tracking power supply. With a
12V voltage established at pin-12 (Vs), the VCO starts to oscillate, sweeping oscillation frequency
from its start frequency (350 kHz) downward. A gate-driving signal for a low-side MOSFET is
generated at pin-11 with respect to pin-10, and another gate driving signal for a high-side
MOSFET is obtained at pin-15 with respect to pin-14.
Figure 3. Resonant controller IC used in tracking power supply
Figure 4 shows the oscillograms of the two gate driving signals, when the IC alone is powered on
by a 12V DC supply. A dead time of about 280ns, during which both signals are at low level, exists
between the two gate signals. Such a dead time avoids shoot-through of the two power MOSFETs.
It also allows zero-voltage switching as will be explained later.
The frequency of the two signals is controlled by a voltage at pin-7, which is connected to the
output of an opto-coupler. The frequency is about 200 kHz with 0V at pin-7 and 100 kHz with 2V at
pin-7.
Figure 4. Scope photo of two gate driving signals
6