IC-DC_17 Datasheet, PDF (14/19 Pages) IC-Haus GmbH – 2-CHANNEL BUCK/BOOST DC/DC CONVERTER

iC-DC
2-CHANNEL BUCK/BOOST DC/DC CONVERTER
REVERSE POLARITY PROTECTION
Rev B1, Page 14/19
A protective switch inserted between supply VB and pin
VBR protects the entire system against reverse polarity.
This can also be used to implement an Autarky function
(see AUTARKY FUNCTION). By connecting VB to VBR
the reverse polarity protection circuit can be bridged to
improve the current carrying capacity and the overall
efficiency, especially if low supply voltages are used
(Figure 5).
24V _CVB
1μF
CVBR
1μF
VB
REVERSE
PROTECT.
INTERNAL
SUPPLY
VBR
LVBH
22μH
VBL VHL
4...36V
CVB
1μF
LVBH
22μH
Figure
VBROK
6: ProtectionVOaLgTAaGinE st
reverse^Bp^UCo^Klarity
active,
NA^CU^VT ^{BR forMVOBNIT=OR24 V}
AUTARKY
BOOST
1
VB
REVERSE
VBR VBL VHL
TOK
4V _CVB
1μF
DETECT.
THERMAL
SHU^CT^VD^BO^RWN
ERROR DET¹E⁰C^μT^F.
LVBH
CONTR^VO^HL
22μH
CVH
3.3μF
PROTECT.
VB
VBR VHV1BL VHL
INTERNAL
SUPPLY
BIAS
CVH1
3.3μF
RREF OSCILLATOR
VCC1
iC-DC ^Figure
5:
VBROK
Protection
a^VMOg_OLNa^TIATin^GOs^ERt
reverse
p^BUo^Cl^Karity
deacti-
vNaAtUeTd, bridges VB to VBR
RREF
20k
AUTARKY
BOOST
1
DETECT.
TOK
THERMAL
SHUTDOWN
CONTROL
VCC1 _FigVCuCr2e
The reverse polar_Ei_Rty_ROp_Rr_Do_Et_Te_ECc_Tt_.ion switch is current lim_R-₁
ited to the maximum mean current consumption of the
R3
REF^RPE_RER^VOE^ETN^REC^SCE^ET.
INTERNA1L
SUPPLY
ELINNV.-R1EG.1
OUTPUT
VEBNRVO2 K ENABLE
7: ProtectionVOaLgTAaGinE st
C^NF^ACG^U1^{VT BRC5VVfCOo}/C3N^r.1F3^AM:IVVGUO/^TRU^BNAR1IR:^TA=R^KOT2YIR4ONV
1.5...5.5V
SWITCHING REGULAT_COR_VCC1
POE1
1μF
SUPPLY
SWITCH 1
reverse^Bp^UCo^VKl^Ha²rity acti_Cv_Ve_H,₂
BO_VO_CS_CT₂
3.3μF
system
(CVBR)
(Electrical Ch_BIa_ASracteristics
mu_Rs_Rt_Eb_F e c_Oo_Sn_CIn_LLe_ATc_Ote_R d to pin
104).
VBR
A capacitor
if higher coi^Rl ²
cu_Rt_R-o_Ef_Ff currents are_REto_FEb_REe_NCs_Eupplied. _{SWITCHING REGULATOR}
This20ckapacitor should have a value of at least 1 µF at
vIttoeir^{Rsps4repo2ovpsiodsleaTCiLbIO}r^FNlifG.Kteu^-y^{R2rEtt(GohF.2eiEug3VrRs.}u^CR3ceCVr^{Oie/2rR2SDT:tc.HHhE5D}9u^UEVTeE,^TR/EiTRtDCMP^Er3p2OTyCA:a^R.rWLTo4g^.wNteeitc1hSSWU^t7iPpI^vT)^PC.er^LHYoH2^{stCeewOcrNieGttPTic,NoROhOD}in^Et^LA2amatgGup^NasiDtinnnsV^1Cot^μVBtFer^{C1eRdC.5-2...5.5V}
2
1
TE
iC-DC ^{a supply voltage of VB = 24 V (Figure 6). With very}
small suppl^Ey^Nv^Vo¹ ltagOeUTsPUthT e value must be greater in or-
V_dC_eC1_{r toVCcCa2ter}^EN_fo^V_r² _the^EN_h^A_i^B_g^L_h^E _{er power consumption during}
R1^sthtaerltou_Rwp3^.eTr _shheCuF^vt_Gdo1oltawgne^C5VV_tCOh/^a_C3Nr.1^tF3_e:IV^VG_s/RU^BhR1:_o^AR_RTl2d^IOmN_{(uEslet cntoricloanl Cgehradrarocptebriestloicws}
that the cur^Vr^Ce^Cn^1,Vt^Cc^C2arrying capacity of the reverse polarity
protection (VBR) is^BIl^Aim^S ited on startup. ^VA^1Os^K the device
powers itRsReElfFfromOSCVILBLARTO, Rthe loa¹ d at VB_VR_2Om_K ust not be
R^tR^oE^oF^high
in²i⁰ti^kated.
as otherRwEFiEsReENcC_&oEnverte₂ r o_Sp_We_Ir_Ta_CHti_Io_NGn_Rc_Ea_GUn_Ln_ATo_Ot_Rbe
The current carrying capacity on startup can
R2^{2asu0pp2pp)ro}_{Rltyxo4.veo1nl0tsa}^C_µ^ugF_Fre^Ge2_soshfaoVfu^3VeB.C3_ld^CVc=/22o:_t^._4h^5nV_uVv^/R_se³₍^:rFR_bt^{4eiegrussretealer7ct)ut.epd.} _{GfANoDrcACapVG}^a_{NBcDRitoartoafVCC1}^be
approx_Ei_Nm_Va₁ tely_OMd_UOTe^VN_Ps^OI_UTc^L_TOTr_RAib_IGNe^EGd by
ENV2 ENABLE
VCCT2EST
I(VBR) = V(VB)
CONFIGURATION
Equation
−1mA
∗
V
3:
(3)
2
R1
R3
R2
CFG1
CFG2
VCC1:
5V/3.3V/R1:R2
VCC2:
3.3V/2.5V/R3:R4
iC-DC
R4
GNDA GND
TE