PEB2023 Datasheet, PDF (11/25 Pages) Siemens Semiconductor Group – ISDN DC Converter Circuit IDCC

PEB 2023
PEF 2023
Overview
Figure 4 shows the PEB/F 2023 in flyback configuration with transformer isolation using
supply voltage range 3. This application circuit is used to supply the internal IC’s of the
NT from the U-interface and also to supply the S-interface in case of restricted power
mode. The DC/DC-converter begins operating when the input voltage exceeds 38V
(U_ZD+8V, see supply voltage range 3). In the start-up phase the PEB/F 2023 is supplied
through V_S. After this start-up phase, the PEB/F 2023 is supplied via V_EXT (power
housekeeping input) and the DC/DC-converter will operate until the input voltage falls
below 20V (input undervoltage detection). For power saving reasons the value of resistor
R₆ is as high as possibile.
The maximum static V_S supply voltage in this example is 120V. How to get a higher
maximum dynamic V_S supply voltage see chapter „1.6 Surge Protection“ on pages 14
and 15.
To get a very fast input undervoltage detection see chapter „1.7 Fast Input Undervoltage
Detection“ on page 15.
41 (20) ... 120 V
ZD₁
BZV55C33
R₆
10ΜΩ/10%
N1
R₅
0.47µF
0.56Ω/5%
20%
C_{5 +}
T₁
BSP 89
C₆ +
100µF
20%
7 11 12 5 6 2 4
V_S UV UVx V_EXT C_SS I_P GA
PEB 2023
PEF 2023
GND RC ^VREF ^VP SYNC COMP ^VN
3 14 1 9 13 8 10
0V
R₁
39ΚΩ
5%
C₁
1nF
5%
R₂
47ΚΩ/5%
+ _C3
1µF
20%
C₂
100nF
10%
BAW 76
R₃ 33ΚΩ
1%
D₁
R₄
68ΚΩ/1%
+ ^C₄
N3
10µF
20%
BYS 21-45
D₂
C_L1 ⁺
N2a _220µF
20%
+5V
R_Load1
82Ω/1%
AAAAAA^{0 V}
C_L2 ⁺
N2b _68µF
20%
D₃
BAS 21
R_Load2
3.9ΚΩ/1%
- 42 V
BYS 21-45
D₄
C_L3 ⁺
N2c _100µF
20%
R_Load3
130Ω/1%
2.2 V
Figure 4
PEB/F 2023 in Flyback Configuration with Transformer Isolation
Semiconductor Group
11
08.97